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Date: Tue, 23 Mar 1993 12:50:21 -0600
From: TELECOM Moderator <telecom@delta.eecs.nwu.edu>
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To: ptownson@gaak.LCS.MIT.EDU
Subject: tdd.specifications
Status: RO
>From CER2520@ritvax.isc.rit.edu Tue Mar 23 08:36:13 1993
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Date: 23 Mar 1993 13:36:13 -0500 (EST)
From: "Curtis E. Reid" <CER2520@ritvax.isc.rit.edu>
Subject: Request to put in telecom-archives at lcs.mit.edu
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Status: R
PAT,
Can you put the TDD specifications in the TELECOM-ARCHIVES at lcs.mit.edu?
Maybe call it tdd.specs ? I get so many requests for the specifications that I
think it might be justified by keeping a separate file that you and I can tell
readers to pull this file out from the archives. What do you say? Thanks!
--Curtis
-----CUT HERE---------
Specifications For TDD Data Transmit/Receive
All TDD manufacturers follow these specs but no tolerance level is given:
1. Acoustic coupling (standard G- and K- type handset)
Input level: 65 dB SPL minimum / 110 db SPL maximum
-4 2
(0 dB SPL = 2 x 10 dyne/cm )
Output level: 95 dB SPL minimum / 100 dB SPL maximum
(acoustic pressure to produce a -9 dBm
signal at the telephone set line terminals
on an average loop)
2. Direct modular connection
Connector: standard 6-position modular jack
USOC No.: RJ11C
Input level: -50 dBm minimum / 0 dBm maximum
Output level: -13 dBm minimum / -9 dBm maximum
3. Modem
Modulation method: Frequency Shift Keying
Mark frequency: 1400 Hz +-5 Hz
Space frequency: 1800 Hz +-5 Hz
Signal to noise ratio: 13 dB
Carrier to data delay: 180 ms
Carrier to hold time: 156 ms
4. Protocol
Code: Baudot
Mode: Half duplex
Transmissions: Asynchronous
Start bit: 1
Stop bit: 1
Data bits: 5
Parity: None
Data rate: 45.5 baud (buffered)
Note: The above information is from Plantronics, Inc. (manufacturer of
the Vu-Phone) and is assumed to be consistent with other brands as the
Vu-Phone is compatible with all other TDD's.
(1985)
--------------
Curtis E. Reid CER2520@ritvax.isc.rit.edu
Rochester Institute of Technology/NTID REID@DECUS.org (DECUS)
P.O. Box 9887 716.475.6089 TDD/TT 475.6895 Voice
Rochester, NY 14623-0887 U.S.A. 716.475.6500 Fax (Business Use Only)
From telecom@delta.eecs.nwu.edu Tue Mar 23 13:53:43 1993
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Date: Tue, 23 Mar 1993 12:53:35 -0600
From: TELECOM Moderator <telecom@delta.eecs.nwu.edu>
Message-Id: <199303231853.AA07817@delta.eecs.nwu.edu>
To: ptownson@gaak.LCS.MIT.EDU
Subject: tdd.specifications
Status: RO
From: "Curtis E. Reid" <CER2520@ritvax.isc.rit.edu>
Subject: Request to put in telecom-archives at lcs.mit.edu
PAT,
Can you put the TDD specifications in the TELECOM-ARCHIVES at lcs.mit.edu?
Maybe call it tdd.specs ? I get so many requests for the specifications that I
think it might be justified by keeping a separate file that you and I can tell
readers to pull this file out from the archives. What do you say? Thanks!
--Curtis
-----CUT HERE---------
Specifications For TDD Data Transmit/Receive
All TDD manufacturers follow these specs but no tolerance level is given:
1. Acoustic coupling (standard G- and K- type handset)
Input level: 65 dB SPL minimum / 110 db SPL maximum
-4 2
(0 dB SPL = 2 x 10 dyne/cm )
Output level: 95 dB SPL minimum / 100 dB SPL maximum
(acoustic pressure to produce a -9 dBm
signal at the telephone set line terminals
on an average loop)
2. Direct modular connection
Connector: standard 6-position modular jack
USOC No.: RJ11C
Input level: -50 dBm minimum / 0 dBm maximum
Output level: -13 dBm minimum / -9 dBm maximum
3. Modem
Modulation method: Frequency Shift Keying
Mark frequency: 1400 Hz +-5 Hz
Space frequency: 1800 Hz +-5 Hz
Signal to noise ratio: 13 dB
Carrier to data delay: 180 ms
Carrier to hold time: 156 ms
4. Protocol
Code: Baudot
Mode: Half duplex
Transmissions: Asynchronous
Start bit: 1
Stop bit: 1
Data bits: 5
Parity: None
Data rate: 45.5 baud (buffered)
Note: The above information is from Plantronics, Inc. (manufacturer of
the Vu-Phone) and is assumed to be consistent with other brands as the
Vu-Phone is compatible with all other TDD's.
(1985)
--------------
Curtis E. Reid CER2520@ritvax.isc.rit.edu
Rochester Institute of Technology/NTID REID@DECUS.org (DECUS)
P.O. Box 9887 716.475.6089 TDD/TT 475.6895 Voice
Rochester, NY 14623-0887 U.S.A. 716.475.6500 Fax (Business Use Only)
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