TR41.9 Part-68 FAQs

Part 68 FAQ

1. ALLOWABLE NON-OPERATIONAL STATES AFTER TYPE A SURGES TR41.9-01-02-017
2. CORDLESS PHONE - On-Hook Impedance ISSUES TR41.9/00-08-038
3. LINE TESTER - 5 Meg DC Resistance ISSUES TR41.9/00-02-006
4. ROLR ISSUES - testing on same digital stations used in different PBX systems TR41.9/00-02-004
5. Facsimile Header Message Requirement TR41.9/99-11-087
6. ROLR ISSUES -testing digital stations TR41.9/00-02-004
7. ROLR ISSUES - digital stations tested through PBX interfaces TR41.9/00-02-004
8. ROLR ISSUES - wireless digital stations and PBX analog trunks TR41.9/00-02-004
9. ROLR ISSUES - criteria for "product family" TR41.9/00-02-004
10. ROLR ISSUES with POWER FAILURE modes TR41.9/99-11-084
11. ROLR ISSUES - wired digital stations and PBX analog trunks TR41.9/00-02-004
12. SURGE PROTECTORS TO GROUND - Rating Issues TR41.9/99-11-063
13. OPS EQUIPMENT TR41.9/98-11-077
14. ALARM DIALERS & line seizure issues TR41.9/99-08-060
15. INTENTIONAL PATHS TO GROUND discussed
16. ALARM DIALERS TR41.9/98-11-077
17. FAILURE CONDITIONS AFTER SURGE STRESSES TR41.9/98-11-077
18. SURGES TYPE B - issues and recommendations TR41.9/98-02-033 , -038, -040
19. HOOK FLASH and OFF HOOK ISSUES TR41.9/98-02-011
20. DIALING WITHOUT NETWORK ADDRESS PURPOSES TR41.9/98-02-011
21. ENCODED ANALOG ATTESTATION FOR ON-PREMISES S/T INTERFACES TR41.9/98-02-005
22. M-LEAD SURGE PROTECTION ISSUES TR41.9/97-05-033
23. PROPER SETTING OF SYNTHESIZED VOICE TR41.9/95-06-020
24. STAND-ALONE SURGE PROTECTORS WITH C.O. CONNECTIONS TR41.9/95-06-021
25. TRANSFERABILITY OF REGISTRATION TR41.9/95-06-023
26. LEAKAGE AND COMPONENTS RATING TR41.9/95-06-022


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1.
ALLOWABLE NON-OPERATIONAL STATES AFTER TYPE A SURGES
TR41.9-01-02-017
BACKGROUND:
A manufacturer is requesting TR41.9’s clarification on the permissible
states of the EUT after the Type A surges of 68.302(c). The manufacturer
wants to incorporate the surge protector as described in the attached
specification sheet. This spec sheet states, among other things: "After a
Type A surge the equipment can be faulty, provided that the fault mode
causes the equipment to be unusable. The high current Type A surges
(101160, 200 A and 10/560, 100 A), will cause the TISP4xxxL3BJ to fail
short circuit, giving a non-operational equipment pass to Type A surges."
(see attached sheet on the TR41.9 web site contribution
TR41.9-01-02-017). However the device as described would cause the
supplier's EUT to place a short circuit (permanent off-hook) across tip
and ring.
ISSUES/PROBLEMS/QUESTIONS:
1. Are non-operational states after Type A surges allowed to include a
short-circuit across Tip and Ring? 2. How widespread is the
misunderstanding of the fail-safe criteria after Type A surges? How can
suppliers be made more aware of the requirements? 3. What is a clear
definition of acceptable “non-operational states” for the EUT after Type
A surges?
AFFECTED P68 SECTION(S):
68.302, 68.312(i)
RECOMMENDATION:
1. The equipment manufacturer is responsible for compliance of the
complete, final assembled equipment . The component as described is not
Part 68 compliant, since it allows the final assembled equipment to
provide a short across the line, which is an off-hook condition. This
violates the requirements of Section 68.312(i). Equipment may not go
off-hook permanently due to a fault mode. Section 68.302 allows a failure
mode, but the failure mode is applicable only if the fault is readily
visible to the user so that the equipment can be disconnected
immediately. 2. Suppliers must not misunderstand the term
“non-operational”, which does NOT mean “permanent off-hook or short” of
the tip and ring interface. Suppliers may consult this site, attend TIA
TR41.9 quarterly meetings, obtain TR41.9's contributions, or join
TR41.9's mail reflector list. 2. Acceptable non-operational states of the
EUT after Type A surges are: permanent on-hook (idle), permanent opening
of the tip and ring line. On the other hand, the EUT must be able to
continue to go on-hook and off-hook after Type B surges. The equipment in
any case is never allowed to be permanently off-hook.
DATE OF RECOMMENDATION: 2-21-2001


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2.
CORDLESS PHONE - On-Hook Impedance ISSUES
TR41.9/00-08-038
BACKGROUND:
A telco investigated a cordless phone with the feature: "Press any key to
cancel Find." Pressing the Talk key during a Find signal did cancel Find,
but it also caused the phone to go off-hook. The telco claimed this
violated 68.312(i). It was said that, stripped to its essence for this
issue, 68.312(i) reads: "[T]erminal equipment shall not by design leave
the on-hook state . . . for any other purpose than to request service or
answer an incoming call . . . ." It was claimed this phone was designed
to go off-hook when canceling a Find signal, even absent any indication
that a user might want to request service or answer a call. If the phone
both cancelled Find and went off-hook during (and only during) incoming
ringing, that could have been acceptable, the telco said. The telco
explained one possible network harm due to this as follows. When C.O.
dial tone resources are already fully allocated, as during an area
emergency or during the busy hour, one additional off-hook event can
delay the presentation of dial tone to the next customer. This would
degrade service to the next customer. This could be serious if the
customer needed to make an emergency call. It was also stated that the
user might not know they had taken the phone off-hook, so their line
might be busied out unknowingly at an important time. Although not a
network harm issue, this could inconvenience the household, making it
difficult to place or receive emergency calls. The telco did not propose
to recall any phones, because the predicted incidence of network harm
problems was infrequent and numerically small. However, it was requested
that the Part 68 FAQ be updated to inform interested parties and improve
compliance going forward.
ISSUES/PROBLEMS/QUESTIONS:
The claimed rule violation was that the Talk key both canceled Find (or
Page), and simultaneously took the phone off-hook, when a Find signal was
active and it could not be certain the user intended to request service
or answer a call. Thus by design the phone went off-hook for a purpose
other than requesting service or answering a call.
AFFECTED P68 SECTION(S):
68.312(i)
RECOMMENDATION:
It was recommended that cordless phone suppliers, in future products,
prevent the Talk key (or equivalent) from causing a phone to go off-hook
while canceling a Find or Page signal, unless there is simultaneous
incoming ringing or another credible indication the user may intend to go
off-hook.
DATE OF RECOMMENDATION: 8-15-2000


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3.
LINE TESTER - 5 Meg DC Resistance ISSUES
TR41.9/00-02-006
BACKGROUND:
A manufacturer has a circuit that is to be connected in series with
FCC-registered equipment. The circuit has a momentary manual switch that,
when depressed, will allow the testing of the different conditions on the
phone line. When the switch is not depressed, the unit passed all
applicable tests of Part 68 , including surge type B, etc. When the
switch is depressed and held on for the Part 68 test to be run (it is a
momentary switch, therefore, the switch is normally open), the resistance
presented to the line is less than 5 meg, thus Section 68.312(b)(1)
criteria is not met. The switch is intended to be depressed when the unit
is installed or when the line is being tested, however, a person would
have to press the switch to do this.
ISSUES/PROBLEMS/QUESTIONS:
1. Can this device be submitted for certification under Part 68 as a line
tester, with instructions in the user's manual to warn the user of the
non-compliance state? What are the harms presented to the network? 2.
What are the options to certify this equipment, if the response to issue
1 is negative?
AFFECTED P68 SECTION(S):
68.312(b)(1)
RECOMMENDATION:
1. The product is similar to a sophisticated punch-down block (but with
modular connectors) that allows for connection of the telephone lines to
separately FCC registered equipment (such as telephone sets) via inside
wiring. It was made clear that this equipment’s primary function was not
a line tester but a distribution module. As part of the product’s
secondary functions, a mechanical, momentary, switch marked “test” is
provided and when the switch is depressed, it allows the testing of
different conditions on the phone lines. However, when the switch is
depressed, the equipment presented a low resistance (much less than the
required 5 Meg Ohms) that does not comply with Section 68.312 (b) (1).
The main concern was that when the switch is depressed and the resistance
presented to the line is less than 5 Meg Ohms, the CO equipment will
detect this low current which corresponds to neither a true off-hook nor
true on-hook state and this will prevent the carriers from conducting
normal, usual line tests. The carriers mentioned that the CO line tests
might be performed at any time of the day, not just in the middle of the
night. The carriers maintained that this prevention of carriers’
performance of line testing is interfering with CO test functions. The
consensus was that the equipment may only be registered with a Z ringer,
or the manufacturer may choose to submit a waiver request to the FCC. 2.
Some of the recommended options are: The device may be registered as a
Type Z ringer which is a conditional registration; this comes with its
own limitations (requires telco's assent to connect). The manufacturer
may at his own option submit a waiver request to the FCC. The
manufacturer could also redesign to bring the equipment into compliance
in all states.
DATE OF RECOMMENDATION: 2-22-2000


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4.
ROLR ISSUES - testing on same digital stations used in different PBX
systems
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. If several PBXs manufactured by the same company are using the same
digital proprietary station sets, would it be sufficient to only test the
digital proprietary station sets with one representative system and apply
the test results across the entire product line?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
1. No. The test data can only be representative if the PBX systems are of
a product family, using the same interface trunks and the same loss plan
and the same digital proprietary telephone station interfaces.
DATE OF RECOMMENDATION: 11-9-1999


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5.
Facsimile Header Message Requirement
TR41.9/99-11-087
BACKGROUND:
In 1995 (CC Docket 92-90), the FCC issued rules requiring that FAX
machines identify the sender of all messages, implementing provisions in
the Telephone Consumer Protection Act of 1991. The intent was to control
telemarketing cold calls and commercial nuisances such as automatic
message dialers and junk FAX mail. These rules first appeared as section
68.318(c)(3), later moved to section 68.318(d): “Telephone facsimile
machines; Identification of the sender of the message. It shall be
unlawful for any person within the United States to use a computer or
other electronic device to send any message via a telephone facsimile
machine unless such message clearly contains, in a margin at the top or
bottom of each transmitted page or on the first page of the transmission,
the date and time it is sent and an identification of the business, other
entity, or individual sending the message and the telephone number of the
sending machine or of such business, other entity, or individual.
Telephone facsimile machines manufactured on and after December 20, 1992,
must clearly mark such identifying information on each transmitted
message.” Manufacturers of FAX machines seeking Part 68 certification are
also required to include a statement in their customer instructions that
describes this requirement and tells the user how to set up the FAX
header (this is sometimes also called “FAX branding”). A sample of this
statement is required in Exhibit J of the application for certification
(see chapter in the “Part 68 Application Guide” on “Customer
Information”). In April 1997, responding to requests from MCI, Sprint,
and Ameritech (see FCC document 97-117 or TR41.9/97-05-051), the FCC
clarified situations where the originator and the transmitter of a FAX
may be different entities or individuals, specifically with regard to
broadcast services. The FCC defined “sender” as the creator of the FAX
message’s content, not the service who sends it. Consequently, each FAX
must identify the business, entity, or individual who created the FAX
rather than the entity who transmits the message. In cases where the
message originator and sender agree to both be identified on the FAX, it
must be clear which is responsible for the message content and which is
merely the message transmitter.
ISSUES/PROBLEMS/QUESTIONS:
A recent query from a FAX machine manufacturer asked: “… then it seems
that the responsibility for conformity is on the user, so long as we take
the appropriate measures to assure that they can comply and know what
they are doing. Do you agree with this?”
AFFECTED P68 SECTION(S):
68.318(d), “Telephone facsimile machines; Identification of the sender of
the message”
RECOMMENDATION:
The questioner is correct, but to clarify so there is no
misunderstanding, FAX machine manufacturers are required to: 1) Provide a
means to insert the FAX header in every FAX transmission. 2) Follow the
instructions for customer information in the “Part 68 Application Guide,”
specifically: a) Advise the customer about the requirement and the need
to always use the FAX header when sending a FAX (specific language in the
Guide). b) Provide clear and simple instructions to the customer telling
how to enter the required information in the FAX header. c) Include a
copy of these customer instructions in Appendix J of the application for
certification. 3) Manufacturers are further advised to put the header
set-up instructions in an easily accessible location and to make this
process easy, making it easy for their customers to comply with this
requirement.
DATE OF RECOMMENDATION: 11-9-1999


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6.
ROLR ISSUES -testing digital stations
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. Are the station sets required to be tested for the VC ROLR
requirements by themselves?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
If the station sets are digital and proprietary and cannot be used by
themselves without the system, they must be tested with the system
DATE OF RECOMMENDATION: 11-9-1999


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7.
ROLR ISSUES - digital stations tested through PBX interfaces
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. Through what interface of the PBX must the digital station sets be
tested for VC ROLR? Analog (i.e. loop start) or Digital (i.e. T1) or
both? 2. Should the PBX and the station set be considered as one big
Black Box Telephone for the purposes of VC ROLR testing?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
1. Both. The PBX loss plan plays an important role in the test for the
reason that when the station set was tested through an analog interface
of the PBX, the network perceives the complete entity as one black box
analog giant phone; when the station set was tested through a digital
interface of the PBX, the network perceives the complete entity as one
black box digital giant phone. Thus, different loss compensations will be
applied by the system. Therefore in order to verify the appropriate loss
compensation, the digital station should be tested through both the
analog and digital interfaces of the PBX, unless the PBX does not provide
both types of interfaces 2. Yes, as indicated above.
DATE OF RECOMMENDATION: 11-9-1999


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8.
ROLR ISSUES - wireless digital stations and PBX analog trunks
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. If the PBX only provides an analog interface, must the wireless
station meet the ROLR in all 3 loop lengths, as specified? Should the air
link matter?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
1. Through the analog interface of the PBX, the wireless digital station
set should still be tested for all 3 specified loop lengths. This also
applies to cordless phones (cordless handset working in conjunction with
a base station connected to the network via a regular wireline loop start
line) which must compensate for the losses over the different loop
lengths.
DATE OF RECOMMENDATION: 11-9-1999


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9.
ROLR ISSUES - criteria for "product family"
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. How should product lines be differentiated for the purpose of ROLR
testing ? By family designation? By FCC Registration designation?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
1. Examples of a product family include systems that differ only in
capacity (i.e, 4x8, 6x12 systems, where the "bigger brother" differ only
in the fact that it can accommodate more capacity). Station sets must be
tested for each PBX that is different (not part of the family) as the PBX
loss plan, and its interface trunks as well as station interfaces do have
an effect on the same digital proprietary station sets. A Product family
should be differentiated by the above criteria rather than by FCC
Registration Number, as sometimes, a "big brother" system that has
received the same FCC Registration Number may incorporate additional
interface trunks, etc. than the "little brother" system covered under the
same FCC Number. The key issue in compliance is whether the test data
obtained for compliance is representative enough. When in doubt, ensure
that each station set complies.
DATE OF RECOMMENDATION: 11-9-1999


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10.
ROLR ISSUES with POWER FAILURE modes
TR41.9/99-11-084
BACKGROUND:
Many multifunction corded telephones that use AC-powered power adaptors
now on the market will continue to function as a standard telephone after
loss of AC power to the adaptor, but will loose many of their functions
such as LCD display, speaker-phone, and Volume Control.
ISSUES/PROBLEMS/QUESTIONS:
1. Is it required to provide the Volume Control feature in the event of a
power failure? (Note: Industry Canada CS-03 exempts compliance with the
Volume Control in the case of AC power failure)
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
The receive gain requirements apply to telephone sets that are fully
operational. They do not apply during AC power failure, if a telephone
set is designed to operate with AC-adapter powering.
DATE OF RECOMMENDATION: 11-9-1999


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11.
ROLR ISSUES - wired digital stations and PBX analog trunks
TR41.9/00-02-004
BACKGROUND:
A manufacturer has a PBX that provides analog interfaces (i.e. loop
start) as well as digital interfaces (i.e. T1 1.544 Mbps). The PBX
provides wired proprietary digital station sets and wireless digital
handsets. The station sets must meet the Volume Control (VC) ROLR
requirements starting on January 2000.
ISSUES/PROBLEMS/QUESTIONS:
1. If the PBX only provides an analog interface, must the wired digital
station meet the ROLR in all 3 loop lengths, as specified?
AFFECTED P68 SECTION(S):
68.317
RECOMMENDATION:
1. Through the analog interface of the PBX, the wired digital proprietary
station set must be tested for all 3 loop lengths, the reason being that
when the station set is tested through an analog interface of the PBX,
the network perceives the complete entity as one black box analog giant
phone; when the station set is tested through a digital interface of the
PBX, the network perceives the complete entity as one black box digital
giant phone. Thus, different loss compensations will be applied by the
system.
DATE OF RECOMMENDATION: 11-9-1999


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12.
SURGE PROTECTORS TO GROUND - Rating Issues
TR41.9/99-11-063
BACKGROUND:
The product is a channel bank FXO board containing multiple identical
interfaces that are software-selectable to be either loop start or ground
start interfaces. In the ground start mode, a ring-to-ground solid state
relay circuit is activated by software. In the loop start mode, the
circuit is functionally disabled but the circuit hardware is still
present. The solid state relay in the circuit has a breakdown rating of
less than 1000 V. This caused the interface (in the loop start mode) to
fail the leakage current limitations requirements of Section 68.304 [in
the ground start mode, the interface is exempt from the tests of Section
68.304 and does meet the ground current capabilities requirements of
Section 68.306(e)(1)].
ISSUES/PROBLEMS/QUESTIONS:
The interface incorporates surge protectors to ground which normally
would have operated to clamp hazardous voltages to ground before the
ring-to-ground solid state relay breaks down, however, Part 68 requires
the protectors to be disconnected for the leakage tests, which leaves the
solid state circuit unprotected and thereby allowed to reach its
breakdown voltage. This situation is seen to be unlikely to happen in
real life since the protectors would have operated before the solid state
circuit breaks down. The suggestion of a hardware strap was not seen as
desirable to the manufacturer as the board incorporates several identical
interfaces and the board would have to be removed from the host chassis
backplane for straps to be changed, causing the operation of several
lines to be disrupted.
AFFECTED P68 SECTION(S):
68.304, 68.306(e)(1)
RECOMMENDATION:
If the interface can prove it has dielectric barriers through other
components in the circuit (transformers, relays), in the loop start mode,
with the ground connection removed from the ring-to-ground resistor (and
with the surge protectors removed from the circuit), then it would be
considered compliant with the spirit of Part 68. It was suggested to the
manufacturer to submit his Part 68 application to the FCC with test data
showing compliance as specified, in both the loop start mode and the
ground start mode.
DATE OF RECOMMENDATION: 8-18-1999


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13.
OPS EQUIPMENT
TR41.9/98-11-077
BACKGROUND:
Part 68, Section 68.308(7) gives requirements for OPS equipment. It
states that there are different requirements for different classes of OPS
equipment. What are the differences in the classes are or and where can
one find the definitions for each class of OPS?
ISSUES/PROBLEMS/QUESTIONS:
3 Classes of OPS are referenced in 68.308 , A B and C. Form 730 also
refers to 3 distinct OPS codes.
AFFECTED P68 SECTION(S):
68.308(7)
RECOMMENDATION:
Off-premise station (OPS) ports of premises communication systems (e.g.,
private branch exchanges or key telephone systems) provide dc loop
supervision network control signaling and talking battery to the remote
OPS stations. The difference between each class is dependent on the loop
lengths that can be supported by the OPS ports for the connection of
remote stations. Figure 68.3 (f) in Part 68, Subpart A, illustrates the
various loops supported by the classes of OPS. NOTE: Notwitthstanding the
specification of 16 mA in Figure 68.3(f), it was determined in TR41.9 -
2/99 meeting that the DC conditions for OPS Class A, B and C ports
requirements are stated in FCC 68.308(b)(7)(ii)(c). The dc current into
the OPS line simulator circuit must be at least 20 mA for Class B and C
OPS ports although the minimum dc current for the Figured 68.3(f) OPS
loop simulator is 16 mA. Testing performed on an OPS port must show
compliance with the 20mA as specified in Subpart D, 68.308(b)(7)(ii)(c),
where the technical requirements reside.
DATE OF RECOMMENDATION: 8-17-1999


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14.
ALARM DIALERS & line seizure issues
TR41.9/99-08-060
BACKGROUND:
A manufacturer markets an alarm control panel with associated control
devices. In the event of an emergency situation, the alarm control panel
would seize the line, pulse the line at a rate of 100 pps for 1 second to
signal the other control devices that are connected to the telephones on
the inside wiring of the house. Upon detecting this pulse signal, each
associated control device would disconnect the telephone instrument to
which it is connected, thus freeing the telephone line for the alarm
control panel to dial out.
ISSUES/PROBLEMS/QUESTIONS:
The issue is on compliance with 68.312(i) that allows terminal equipment
to go off hook only for the purpose of answering an incoming call or
originating a call. This alarm control panel would be going off hook for
purposes other than those allowed. The problems revolve around the line
seizure conditions and characteristics of an alarm control panel. In the
past, this type of devices would be wired in the house ahead of all other
telephone sets (cc USOC RJ31X) so that in the event of an emergency, the
device would disconnect all the other telephones and dial out. In the
present environment, often the alarm device is added to the house after
several telephones have been wired and connected and there is no easy way
to ensure that the alarm control panel will be wired ahead of all other
devices.
AFFECTED P68 SECTION(S):
68.312(i)
RECOMMENDATION:
A. if at least one telephone is already off-hook, there is no issue with
compliance with 68.312(i) [line already off hook] B. If all associated
telephones are on-hook, and the alarm control panel goes off-hook,
performs its pulsing sequence and continues to stay off-hook in order to
subsequently network address (dial out), then it will comply with
68.312(i). This is the suggested design to the manufacturer of the alarm
panel. C. If all associated telephones are on-hook, and the device goes
off-hook, performs its pulsing sequence and then goes on hook to wait for
the associated instruments to free the line, it would technically violate
the requirements of Section 68.312(i). It was mentioned that, however,
this device intends to subsequently use the line to dial out, and the
efforts to clear the line would be seen by network operators as less
"harmful" than if the device were to use the line to open a door phone
controller, for example. It was mentioned that the series of pulses from
the device may be seen as a 100 Hz signal and the signal is then subject
to the signal power requirements of 68.308. If the signal power of the
resulting signal complies with the loop start requirement of -9dBm, then
the device could be considered as Part 68 compliant (given the emergent
circumstances) even though it technically violates the requirements of
Section 68.312(i). This solution is not seen as desirable as the one
suggested in subparagraph B above.
DATE OF RECOMMENDATION: 8-17-1999


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15.
INTENTIONAL PATHS TO GROUND
discussed
BACKGROUND:
Part 68, Section 68.304 allows for intentional operational paths to
ground (as in DID, ground start ) to be excluded from the 1000 V leakage
test. Leads excluded for this purpose must be subjected to the tests of
68.306 (c)(1) for ground integrity demonstration. A manufacturer has an
E1/T1 CSU interface card. In the T1 mode, there is no intentional
operational path to ground. However, in the E1 mode, there is a circuit
to ground that would cause the device to fail the leakage test. This
circuit may or may not affect the transverse balance characteristics of
the T1/CSU.
ISSUES/PROBLEMS/QUESTIONS:
1. Is the circuit for E1 operation considered an intentional operational
path to ground? 2. Should the card have a jumper that would disconnect
the circuit to ground in T1 operation?
AFFECTED P68 SECTION(S):
68.304 Leakage Current Limitations 68.306(e)(1) intentional operational
paths to ground 68.310 Transverse Balance
RECOMMENDATION:
Since the intentional path to ground is not an inherent function for T1
operation, and E1 functions are not within the purview of FCC Part 68,
the exemption for intentional path is not allowed. The terminal equipment
must comply with the requirements of Section 68.308. Alternatively, the
equipment could be designed to effectively disconnect the path to ground
in T1 operation, such as the use of a jumper.
DATE OF RECOMMENDATION: 2-18-1999


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16.
ALARM DIALERS
TR41.9/98-11-077
BACKGROUND:
A manufacturer has a PBX system with a dial out modem, the modem will
only dial out if some of the hardware in the system has crashed. The
modem will dial out to a paging service to contact a technician. The tech
will then take the necessary repair to the PBX system. The autoredial
attempts from the modem can be set well beyond the specification of Part
68 Subpart D section 68.318(b). Would this equipment qualify for
registration as an alarm dialer?
ISSUES/PROBLEMS/QUESTIONS:
According to Part 68, emergency dialers are exempt from the limitations
placed on automatic redialing functions
AFFECTED P68 SECTION(S):
68.318(b)
RECOMMENDATION:
Yes. Note the statement in the November 1997 Order that Emergency alarm
dialers and dialers under external computer control are exempt from these
requirements. Note the definition in the Application Guide for equipment
code AL implies that Alarm dialing systems fire, intrusion, equipment
failure and the like. A internal modem within a terminal equipment, when
used in emergency conditions such as the one described qualifies for the
exemption under Emergency dialers, even though the terminal equipment
primary function is not of an alarm dialer.
DATE OF RECOMMENDATION: 11-18-1998


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17.
FAILURE CONDITIONS AFTER SURGE STRESSES
TR41.9/98-11-077
BACKGROUND:
What constitutes failure for the 68.302 Type A surge test?
ISSUES/PROBLEMS/QUESTIONS:
Surge stresses are environmental conditioning tests.
AFFECTED P68 SECTION(S):
68.302(b)(3)
RECOMMENDATION:
Since surge stresses are conditioning tests, the Terminal Equipment must
undergo all the applicable electrical tests after the surges. Any failure
to comply with the criteria of all applicable Sections of Part 68 after
the surges constitutes a failure. This determination applies to both Type
A and Type B surges. Note: Pursuant to 68.302(b)(3), the Terminal
Equipment is allowed to reach some failure modes in violation of the
transverse balance requirements of Section 68.310 provided that such
failure modes are intentionally designed and that the equipment would
become substantially and noticeably unusable by the user, or an
indication would be given (e.g. alarm) in order for the equipment to be
immediately disconnected from the telephone line.
DATE OF RECOMMENDATION: 11-18-1998


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18.
SURGES TYPE B - issues and recommendations
TR41.9/98-02-033 , -038, -040
BACKGROUND:
The Harmonized Part 68 requires that Surges Type B be performed with the
following failure criteria, specified in Section 68.302(c)(3): "RTE shall
be capable of withstanding the energy of Surge Type B without causing
permanent opening or shorting of the interface circuit and without
sustaining damage that will affect compliance with these rules"
ISSUES/PROBLEMS/QUESTIONS:
1. Need for better definition of "permanent opening", perhaps relating to
a minimum amount of current drawn from the interface. 2. Need for more
precise specification of what can happen after the Surges Type B:
equipment does not need to transmit, etc. 3. Need for better
specification of the tests necessary to be performed after the Surges
Type B (i.e., all tests, a subset of tests, etc.)
AFFECTED P68 SECTION(S):
68.302(c)(3) failure mode
RECOMMENDATION:
It is necessary to perform ALL test for those states achievable after
application of the Type B surge. This is necessary to ensure that
equipment continues to be in compliance with the requirements of Subpart
D of Part 68. Often, the very last test to be performed is the one
yielding a failure to meet the appropriate criteria. A transverse balance
failure for example may not be apparent visually until the equipment is
tested according to Section 68.310. The following premise was used as the
basis for the recommendation: If ALL the required tests were NOT
performed after the Type B surges, equipment that had not undergone this
complete testing after the Type B surges may harbor non-compliance
parameters that would surface later in subsequent modification filings
and would be extremely difficult to trace, specially if different test
labs were used. An operational test alone may not cover the effects of
the Type B surge stress on the terminal equipment. Based on this
potential problem of non-uniformity of test data that could: a. create
widespread complaints to the FCC and b. foster difficulties of tracing
the problems for the manufacturers and test labs TR41.9 recommends to the
FCC Part 68 Review Staff to look for complete applicable test data ( (1)
before stresses, (2) after Type B stresses, and (3) after Type A stresses
in all Part 68 applications. Regarding the state of the equipment after
the Surge Type B, TR41.9 committee agreed that the equipment under test
must go on-hook and off-hook (or provide an idle and active state, for
interfaces not drawing loop current), but other functionalities (data
transmission, DTMF dialing, etc.) are not necessary. Some examples of
equipment conditions after Type B stress and their acceptability: OK
Equipment continues to go on-hook and off-hook Equipment needed to be
reset Cycling of power, whether through commercial power or batteries NOT
OK Equipment remains permanently on-hook Equipment remains permanently
off-hook Replacing components in interface:e.g. fuses, transformers,
relays, etc. Replacing components such as ROM chip in control circuit, or
fuse in power supply circuit
DATE OF RECOMMENDATION: 2-16-1998


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19.
HOOK FLASH and OFF HOOK ISSUES
TR41.9/98-02-011
BACKGROUND:
A manufacturer designs a door phone system comprised of a door bell and a
relay system that would connect a door speakerphone directly to the house
phone. While on the phone with a remote caller, if the owner hears his
house doorbell, he would hookflash, then be connected to the visitor at
the door speakerphone; the outside line is on hold and would be
re-connected after a second hook flash. If the house phone is not being
used at the time a visitor rings the bell, the owner can pick up the
house phone, hook flash, then be connected to the visitor at the door
speakerphone.
ISSUES/PROBLEMS/QUESTIONS:
Would this device violate the requirements of Section 68.312(i)?
68.312(i) states: "Transitioning to the Off-Hook State. Registered
terminal equipment and registered protective circuitry shall not by
design leave the on-hook state by operations performed on tip and ring
leads for any other purpose than to request service or answer an incoming
call, except that terminal equipment that the user places in the off-hook
state for the purpose of manually placing telephone numbers in internal
memory for subsequent automatic or repertory dialing shall be
registerable. Make-busy indications shall be transmitted by the use of
make-busy leads only as defined in §§ 68.3 and 68.200(j)."
AFFECTED P68 SECTION(S):
68.312(i)
RECOMMENDATION:
When the user was already off hook in an ongoing conversation, there is
no harm generated whereas when the user picked up the phone to answer the
doorbell while not requesting network services would be considered as
violating 68.312(k). It was mentioned that the FCC has already allowed
CPE to go off hook in violation of 68.312(k) for programming purposes,
and that the hookflashing situation could be construed as another
application of “exceptional uses”. The hookflash area was considered to
be a “gray” area, and timing considerations were discussed. In the end,
it was concurred that, although the user of a CPE may be the one
initiating the action, and that CPE, not users, fall under the
jurisdiction of Part 68, CPE should not be designed in such a way that
would allow the user to intentionally violate Part 68 rules. Note: The
intent of Section 68.312(k) is to prevent PERMANENT shorting of the
telephone line. Going off hook and drawing dial tone without a request
for network services is a violation of 68.312(k) in the truest sense.
However, since the hookflashing lasts basically for a very short period,
there should be no network harm generated in the practical sense.
DATE OF RECOMMENDATION: 2-16-1998


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20.
DIALING WITHOUT NETWORK ADDRESS PURPOSES
TR41.9/98-02-011
BACKGROUND:
A manufacturer designs a door phone system comprised of a door bell and a
relay system that would connect a door speakerphone directly to the house
phone. While on the phone with a remote caller, if the owner hears his
house doorbell, he would hookflash, dials a 2-digit number, then be
connected to the visitor at the door speakerphone; the outside line is on
hold and would be re-connected after a second hook flash. If the house
phone is not being used at the time a visitor rings the bell, the owner
can pick up the house phone, hook flash, dials a 2-digit number, then be
connected to the visitor at the door speakerphone.
ISSUES/PROBLEMS/QUESTIONS:
Would this device violate the requirements of Section 68.312(i)?
68.312(i) states: "Transitioning to the Off-Hook State. Registered
terminal equipment and registered protective circuitry shall not by
design leave the on-hook state by operations performed on tip and ring
leads for any other purpose than to request service or answer an incoming
call, except that terminal equipment that the user places in the off-hook
state for the purpose of manually placing telephone numbers in internal
memory for subsequent automatic or repertory dialing shall be
registerable. Make-busy indications shall be transmitted by the use of
make-busy leads only as defined in §§ 68.3 and 68.200(j)."
AFFECTED P68 SECTION(S):
68.312(i)
RECOMMENDATION:
It was unanimously concluded that the case where the door controller was
activated by the use of digit dialing, definitively violates 68.312(i).
In the end, it was concurred that, although the user of a CPE may be the
one initiating the action, and that CPE, not users, fall under the
jurisdiction of Part 68, CPE should not be designed in such a way that
would allow the user to intentionally violate Part 68 rules.
DATE OF RECOMMENDATION: 2-16-1998


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21.
ENCODED ANALOG ATTESTATION FOR ON-PREMISES S/T INTERFACES
TR41.9/98-02-005
BACKGROUND:
CS-03 Standard allows S/T interfaces that orginates encoded analog
signals but remain on-premises to be certified without being tested for
signal power; an attestation is required to be submitted to the Industry
Canada to provide assurance that the encoded analog content does not
exceed the -12 dBm limit.
ISSUES/PROBLEMS/QUESTIONS:
1. encoded analog content limitations have been traditionally applied at
the point of origination in Part 68. Even though the interface stays on
premises, the signals can be carried by an NT1 into the network and be
decoded in the network. The NT1, being modular, and can obtain
registration on its own, will not be tested for encoded analog signal
power as it does not generate these signals. 2. the rationale for the
requirements in CS-03 was that it was difficult to obtain test equipment
at the time of the adoption of ISDN in CS-03 (circ. 1990). 3. encoded
analog testing is required of the same S/T interface if it goes
off-premises on common carrier facilities
AFFECTED P68 SECTION(S):
68.308(h)(4) encoded analog content, BRI 68.308(h)(2)(v) encoded analog
content, 1.544 Mbps (T1 and PRI)
RECOMMENDATION:
Since testing is applied at the U interface, there is no technical reason
to use attestation for analog content in lieu of testing at the S/T
interface. The committee agreed to recommend TAPAC to revisit the
exemption as stated in CP-01 and to delete this provision.
DATE OF RECOMMENDATION: 2-1-1998


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22.
M-LEAD SURGE PROTECTION ISSUES
TR41.9/97-05-033
BACKGROUND:
The Harmonized Part 68, Section 68.304 allows for protection paths to
ground to be separately evaluated under 68.306(e)(2), however, under this
section, the protection component must undergo a test voltage of 120V or
300V to ground. M-Lead surge protection to ground on the A side of the
interface is normally a zener rated at 60-80VDC. This device would fail
the new 68.306(e)(2) requirements.
ISSUES/PROBLEMS/QUESTIONS:
Specifically exclude M-lead protection paths to ground, in E&M circuits
on the A side of the interface?
AFFECTED P68 SECTION(S):
68.304 leakage current 68.306(e)(2) intentional protection paths to
ground
RECOMMENDATION:
EUT which have intentional conducting paths to ground and are therefore
deferred from High Voltage AC leakage tests contained in CS-03's
2.2.1/FCC's 68.304 shall, if that path is an operational intentional
path, require only the ground integrity test of 2.3.9.1/68.306(e)(1).
Even if there should also be a protective intentional path to ground in
the same network interface, the operational path takes exclusive
precedence over the protective, negating the requirement for the
I-Leakage test. Only those EUT with protective-only paths to ground shall
require the I-Leakage test of 2.3.9.2/68.306(e)(2).
DATE OF RECOMMENDATION: 5-1-1997


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23.
PROPER SETTING OF SYNTHESIZED VOICE
TR41.9/95-06-020
BACKGROUND:
Multi-media devices have the capabilities of an answering machine, i.e.
they allow recording from an internal/external source and playback of
machine-generated messages. In some cases, the MIC input is located on
the host computer that is not included as part of the registration
envelope, making this input a non-registered connection. Host software
may also allow volume adjustments for recording and/or playback.
ISSUES/PROBLEMS/QUESTIONS:
Does the card manufacturer have to set the maximum level?
AFFECTED P68 SECTION(S):
68.308(b) Voice-band metallic signal power
RECOMMENDATION:
The card must limit the maximum output to the network to less than the
allowed maximum level of its class of service (i.e. less than -9 dBm for
loop start, less than -15 dBm for tie trunk, etc.), in the worst case
scenario (with the input levels to the card at maximum, etc.).
DATE OF RECOMMENDATION: 6-1-1995


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24.
STAND-ALONE SURGE PROTECTORS WITH C.O. CONNECTIONS
TR41.9/95-06-021
BACKGROUND:
Surge protectors are getting more and more sophisticated. Some are
actually power line outlet bars with telephone jacks where front-end
secondary protection circuitry is provided for tip and ring inputs. This
may include series fusible resistors and parallel varistors.
ISSUES/PROBLEMS/QUESTIONS:
1. The varistors may draw enough current to provide a high load on the
line during ringing. 2. Potential open circuit of the fusible resistors
after the surges (not allowed under Method B of 68.302). 3. Are these
devices required to be registered under P68?
AFFECTED P68 SECTION(S):
68.312 (b) On hook impedance 68.302 (d) & (e) Metallic and Long. Surges
RECOMMENDATION:
If these devices are not electrically transparent (i.e with resistors in
series and surge suppressors in parallel with tip and ring of the
associated registered equipment), they must be P68 registered, due to
their potential effect on compliance of the associated registered
equipment with the requirements of 68.302 (Method B surges), 68.304
(Leakage), 68.308 (in-band and out-of-band noise), 68.310 (Longitudinal
Balance) and 68.312 (on hook impedance).
DATE OF RECOMMENDATION: 6-1-1995


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25.
TRANSFERABILITY OF REGISTRATION
TR41.9/95-06-023
BACKGROUND:
Modem and other PC modules have been registered as OEM devices to be
installed in a final assembly. Differences between OEM devices: modem
cards vs. modules plugging into a host mother board that provides tip and
ring and ground traces to backplane of host systems, etc.
ISSUES/PROBLEMS/QUESTIONS:
Non-compliance may occur causing longitudinal balance and leakage
problems if tip and ring traces are too close to ground through various
paths on the host system. Host devices may have other components (such as
filter caps) to ground that may cause on-hook impedance problems, etc.
Non-compliant network connectors may be provided by the host assembly.
AFFECTED P68 SECTION(S):
68.304 Leakage Current Limitations, 68.308 Signal Power Limitations,
68.310 Longitudinal Balance, 68.312 on hook impedance
RECOMMENDATION:
see Appendix P of the Application Guide for component device guidance.
Further work will be done on this issue.
DATE OF RECOMMENDATION: 6-1-1995


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26.
LEAKAGE AND COMPONENTS RATING
TR41.9/95-06-022
BACKGROUND:
A circuit designer wanted to use the same telephone interface coupling
transformer, used in a similar device that is P68 registered. When he
found out from the transformer manufacturer that the component is rated
lower than the P68 required 1000 V, he contacted the FCC to see if he
could still use the component. At the same time, he had the component
tested at a private lab and the sample tested happened to pass the
leakage test of 68.304. He wanted the FCC to allow him to use the
component. Component rating of the interface has been required by the FCC
as part of Exhibit E of the P68 application to ensure that dielectric
components used in the interface are designed to withstand the proper
voltage - not just in the sample tested.
ISSUES/PROBLEMS/QUESTIONS:
How should components be rated and how do these ratings relate to Part 68
requirements? Should the leakage current limit be reduced?
AFFECTED P68 SECTION(S):
68.304 dielectric barrier and leakage current limitations
RECOMMENDATION:
a. If a component in the telephone interface circuit is relied upon for
dielectric isolation barrier, then it is recommended that this component
be rated at 1000 Vrms. b. There is no recommendation for changing the
present maximum allowed leakage current of 10 mA peak.
DATE OF RECOMMENDATION: 6-1-1995