HACKNET PRESENTS:

THE FOLLOWING IS FROM "REFERENCE DATA FOR RADIO ENGINEERS
FIFTH EDITION, PUBLISHED BY ITT.

SIGNALING IN THE TOLL PLANT 

SIGNALING OVER LONG-HAUL INTERTOLL TRUNKS USES
TECHNIQUES WHEREBY SIGNALING INFORMATION IS TRANSMITTED AT
AUDIO FREQUENCCIES WITHIN THE VOICE CHANNEL (IN-BAND
SIGNALING) OR JUST ABOVE THE VOICE-CHANNEL SPECTRUN (OUT OF
BAND SIGNALING).  LEVELS ARE COMPARABLE TO SPEECH LEVELS.
USE OF ALTERNATING-CURRENT TECHNIQUESS IS MANDATORY IN
FREQUENCY-DIVISION-MULTIPLEX SINGLE-SIDEBAND CARRIER
SYSTEMS, AS NO DIRECT-CURRENT PATH EXISTS THROUGH THE
EQUIPMENT.  SOME SHORT-HAUL SYSTEMS HAVE BEEN DESIGNED THAT
MAKE USE OF FREQUENCY SHIFT OF THE CHANNEL CARRIER TO
TRANSMIT SUPERVISORY AND NUMERIC SIGNALS, BUT DIFFICULTIES
IN APPLYING THIS TECHNIQUE TO WIDE-BAND CARRIER SYSTEMS HAS
LIMITED THE FREQUENCY-SHIFT KEYING TO SYSTEMS HAVING ONLY A
FEW CHANNELS.  E AND M CONTROL OF ALTERNATING-CURRENT
SIGNALING IS ALMOST UNIVERSALLY USED IN THE UNITED STATES
AND CANADA.  SEPARATE SIGNALING SYSTEMS MAY BE USED TO
TRANSMIT SUPERVISORY AND NUMERIC SIGNALS.
                                       
IN BAND SIGNALING SYSTEMS-AMERICAN TELEPHONE AND TELEGRAPH
COMPANY                                

     PRESENT DESIGNS FOR APPLICATION TO TOLL TRUNKS HAVE
THE FOLLOWING CHARACTERISTICS:
FREQUENCY:
  FOR 4-WIRE TRUNKS:   2600 HERTZ
  FOR 2-WIRE TRUNKS:   2600 HERTZ
                       2400 HERTZ
PULSING CHARACTERISTICS:
  8 TO 12 PPS WITH BREAK OF 46 TO 76 PERCENT
    PROVISION IS MADE TO MINIMIZE MUTUAL INTERFERENCE
BETWEEN SIGNAL AND SPEECH CIRCUITS BY THE USE OF A GUARD
CIRCUIT WHICH INHIBITS OPERATION OF THE RECEIVER WHEN
FREQUENCIES OTHER THAN SIGNAL TONE ARE PRESENT.  ADDITIONAL
ARRANGEMENTS INSERT A TONE BLOCKING FILTER IN THE RECEIVING
SPEECH PATH WHEN CALLS ARE MADE TO LINES WHICH DO NOT
RETURN ANSWER SUPERVISION.

MULTIFREQUENCY TRUNK SIGNALING

    TO INCREASE THE SPEED OF SETTING UP INTEROFFICE
CONNECTIONS, MULTIFREQUENCY SIGNALING IS OFTEN APPLIED TO
TRUNK CIRCUITS FOR TRANSMISSION OF SWITCHING INFORMATION.
DIGITAL INFORMATION IS TRANSMITTED BY COMBINATIONS OF 2 OF
THE FOLLOWING 5 AUDIO FREQUENCISE: 700, 900, 1100, 1300 AND
1500 HERTZ.  A SIXTH FREQUENCY OF 1700 HERTZ IS USED IN
COMBINATION WITH THE 1100-HERTZ FREQUENCY AS A "PRIMING"
SIGNAL AND IN COMBINATION WITH THE 1500-HERTZ FREQUENCY AS
A "START" SIGNAL.  TABLE 15 GIVES THE STANDARD
MULTIFREQUENCY SIGNALING CODE.  EACH TONE IS CUSTOMARILY
TRANSMITTED AT A LEVEL OF -6 DBMO.     

TABLE 15
MULTIFREQUENCY TRUNK SIGNALING CODE
-----------------------------------------------------------
                     FREQUENCIES IN HERTZ
           ------------------------------------------------
  SIGNAL      700    900    1100    1300   1500    1700
===========================================================
 PRIMING (KP)                 X                      X
  KP2                                  X             X
 START   (ST)                                 X      X
   0                                   X      X
   1           X      X                
   2           X              X
   3                  X       X        
   4           X                        X                                     
   5                  X                 X
   6                          X         X
   7           X                               X
   8                  X                        X
   9                          X                X
 CODE 11       X                                     X
 CODE 12              X                              X
===========================================================
NOTE:  PRIMING IS ALSO KNOWN AT KP OR "KEY PULSE"
       START IS KNOWN AS ST            
       KP2 OR KEY PULSE 2 IS 1300+1700 HZ.


DTMF (DUAL TONE MULTI-FREQUENCY) TOUCH TONES


THESE TONES ARE THE ONES GENERATED BY A NORMAL TOUCH-TONE
PHONE.  THERE ARE 4 ADDTIONAL BUTTONS ON THAT ARE USED ON
SOME SYSTEMS.  A SILVER BOX IS A PAD THAT CAN GENERATE ALL
16 DIGITS

EACH NUMBER IS GENERATED BY TWO TONES, ONE FROM A HIGH
GROUP AND ONE FROM A LOW GROUP.

                     DTMF FREQUENCIES
===========================================================
               (              HIGH TONE
LOW TONE (HZ)  (  1209 HZ    1336 HZ   1477 HZ   1633 HZ
-----------------------------------------------------------
   697         (    1          2          3        FO
   770         (    4          5          6        F
   852         (    7          8          9        I
   941         (    *          0          #        P
-----------------------------------------------------------

THE RIGHT COLUMN (1633HZ COMBINATIONS) IS USED BY THE
MILITARY FOR PRECEDENCE, A HIGHER PRECEDENCE CAN PRE-EMPT A
LOWER PRECEDENCE CALL.  THE ORDER OF PRECEDENCE IS FLASH
OVERRIDE, FLASH, IMMEDIATE AND PRIORITY.  REGULAR CALLS ARE
ROUTINE.  THEY HAVE DIFFERENT PURPOSES ON OTHER SYSTEMS,
AND ARE SOMETIMES KNOWN SIMPLY AS A B C & D.


NOTES ON BOX BUILDING
    THERE ARE SEVERAL IC CHIPS AVAILABLE THAT GENERATE DTMF
TONES  MOTOROLA MC14410 FO HEP C4056P WILL DO THE JOB
NICELY.  RADIO SHACK HAS A SIMILAR CHIP WITH INFO INCLUDED.
YOU WILL NEED A 16 BUTTON PAD DECODED INTO ROWS AND
COLUMNS.


BUILDING A BLUE BOX (WHICH GENERATES THE INTEROFFICE TRUNK
SIGNALING TONES) IS MORE DIFFICULT AS NO SINGLE CHIP EXISTS
THAT WILL GENERATE ALL THE TONES EASILY.

A TEXAS INSTRUMENTS TI-99/4 WILL GENERATE ALMOST ANY TONE
COMBINATION YOU WANT WITH THE BASIC CALL SOUND STATEMENT.
IT IS RELATIVELY EASY TO WRITE A BASIC PROGRAM THAT WILL
PLACE THE FREQUENCIES IN AN ARRAY USING READ DATA
STATEMENTS AND THEN SCAN THE KEYBOARD SO THAT EACH KEY WILL
GENERATE A PARTICULAR SET OF TONES.  E.G. CALL SOUND
(DURATION, TONE1, VOLUME, DURATION, TONE2, VOLUME).  WHERE
DURATION AND VOLUME ARE CONSTANTS AND TONE1 AND TONE2 ARE
THE FREQUENCIES YOU WANT TO GENERATE.  THEY CAN BE SET
EQUAL TO THE VALUE STORED IN THE ARRAY AT A POSITION
CORRESPONDING TO THE ASCII RETURNED FROM THE KEYBOARD FOR
THAT KEY'S TONE PAIR.  IN MY PROGRAM THE LEFT SIDE OF THE
KEYBOARD BECOMES A DTMF GENERATOR AND THE RIGHT SIDE MAKES
INTEROFFICE (MF) TONES (BLUE BOX).  YOU COULD PUT IN
SUBROUTINES FOR AUTO-DIALING AND OTHER FRILLS.  I THINK YOU
COULD MAKE A BATTERY POWER SUPPLY FOR THE TI/99 AND MAKE IT
PORTABLE ENOUGH TO CARRY TO PHONE BOOTHS.
   I CAN'T REALLY RECOMMEND THAT YOU TRY BOXING UNLESS YOU
REALLY KNOW WHAT YOU ARE DOING AND REALIZE THE PENALTIES
FOR BEING CAUGHT!  JUST BEING ABLE TO GENERATE THE TONES
WILL BE OF LITTLE USE TO YOU UNLESS YOU KNOW WHAT TO PUNCH
IN AND WHAT IT IS DOING.  MOST EXPERIENCES PHREAKS GAVE UP
BOXNG YEARS AGO.  REST ASSURED THAT MA BELL HAS EXPENDED A
GREAT DEAL OF ENERGY TO PUT AN END TO BLUE BOXING.  IN MANY
STATES POSSESION OF A BLUE BOX IS A CRIMINAL OFFENSE.  THE
BEAUTY OF THE TI-99/4 IS THAT WHEN IT IS TURNED OFF OR THE
PROGRAM "NEWED" THEN IT BECOMES AN GARDEN VARIETY MICRO.  I
NEVER HEARD OF A JURY CONVICTING ON THAT KIND OF EVIDENCE.
                                       
    IF YOU LIVE IN A MEDIUM TO LARGE CITY AND HAVE ANY KIND
OF ESS (IF YOU HAVE TOUCH TONE SERVICE, CALL WAITING, CALL
FORWARDING OR THREE WAY CALLING AVAILABLE THEN YOU HAVE AN
ESS), FORGET ABOUT BLUE BOXING, IT WON'T WORK ANYWAY AND
YOU WILL ALMOST SURELY BE CAUGHT FOR ATTEMPTING IT.
   IF YOU ARE SERVED BY AN INDEPENDENT TELCO, (NOT BELL, OR
GTE OR CONTINENTAL) OR HAVE AN OLDER EXCHANGE YOU ARE LUCKY
INDEED, YOU CAN PROBABLY GAIN ACCESS TO ATT LONG LINES, AS
WELL AS THE OCC'S (SPRINT, MCI, ETC.) AND USE YOUR BLUE BOX
IN THE STYLE OF THE GREAT PHREAKS OF THE 60'S AND EARLY
70'S.