home *** CD-ROM | disk | FTP | other *** search
-
- THE MARK TABAS ENCOUNTER
- SERIES PRESENTS:
-
- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
- BETTER HOMES AND BLUE BOXING
-
- PART I
-
- THEORY OF OPERATION
-
- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-
- TO QUOTE KARL MARX, BLUE BOXING HAS
- ALWAYS BEEN THE MOST NOBLE FORM OF
- PHREAKING. AS OPPOSED TO SUCH THINGS
- AS USING AN MCI CODE TO MAKE A FREE
- FONE CALL, WHICH IS MERELY MINDLESS
- PSEUDO-PHREAKING, BLUE BOXING IS
- ACTUAL INTERACTION WITH THE BELL
- SYSTEM TOLL NETWORK. IT IS LIKEWISE
- ADVISABLE TO BE MORE CAUTIOUS WHEN
- BLUE BOXING, BUT THE CAREFUL PHREAK
- WILL NOT BE CAUGHT, REGARDLESS OF WHAT
- TYPE OF SWITCHING SYSTEM HE IS UNDER.
- IN THIS PART, I WILL EXPLAIN HOW AND
- WHY BLUE BOXING WORKS, AS WELL AS
- WHERE. IN LATER PARTS, I WILL GIVE
- MORE PRACTICAL INFORMATION FOR BLUE
- BOXING AND ROUTING INFORMATION.
-
- COMMUNICATING WITH TRUNKS. TRUNKS MUST
- NOT BE CONFUSED WITH SUBSCRIBER LINES
- (OR "CUSTOMER LOOPS") WHICH ARE
- STANDARD TELEFONE LINES. TRUNKS ARE
- THOSE LINES THAT CONNECT CENTRAL
- OFFICES. NOW, WHEN TRUNKS ARE NOT IN
- USE (I.E., IDLE OR "ON-HOOK" STATE)
- THEY HAVE 2600HZ APPLIED TO THEM. IF
- THEY ARE TWO-WAY TRUNKS, THERE IS
- 2600HZ IN BOTH DIRECTIONS. WHEN A
- TRUNK IS IN USE (BUSY OR "OFF-HOOK"
- STATE"), THE 2600HZ IS REMOVED FROM
- THE SIDE THAT IS OFF-HOOK. THE 2600HZ
- IS THEREFORE KNOWN AS A SUPERVISORY
- SIGNAL, BECAUSE IT INDICATES THE
- STATUS OF A TRUNK; ON HOOK (TONE) OR
- OFF-HOOK (NO TONE). NOTE ALSO THAT
- 2600HZ DENOTED SF (SINGLE FREQUENCY)
- SIGNALLING AND IS "IN-BAND." THIS IS
- VERY IMPORTANT. "IN-BAND" MEANS THAT
- IS IS WITHIN THE BAND OF FREQUENCIES
- THAT MAY BE TRANSMITTED OVER NORMAL
- TELEFONE LINES. OTHER SF SIGNALS, SUCH
- AS 3700HZ ARE USED ALSO. HOWEVER, THEY
- CANNOT BE CARRIED OVER THE TELEFONE
- NETWORK NORMALLY (THEY ARE "OUT-OF-
- BAND AND ARE THEREFORE NOT ABLE TO
- BE TAKEN ADVANTAGE OF AS 2600HZ IS.
- BACK TO TRUNKS. LET'S TAKE A
- HYPOTHETICAL PHONE CALL. YOU PICK UP
- YOUR FONE AND DIAL 1+806-258-1234
- (YOUR GOOD FRIEND IN AMARILLO)
- TEXAS). FOR EASE, WE'LL ASSUME THAT
- YOU ARE ON #5 CROSSBAR SWITCHING AND
- NOT IN THE 806 AREA. YOUR CENTRAL
- OFFICE (CO) WOULD RECOGNIZE THAT
- 806 IS A FOREIGN NPA, SO IT WOULD
- ROUTE THE CALL TO THE TOLL CENTRE
- THAT SERVES YOU. [FOR THE SAKE OF
-
- EXPERIENCED READERS, NOTE THAT THE
- CO IN QUESTION IS A CLASS 5 WITH
- LAMA THAT USES OUT-OF-BAND SF
- SUPERVISORY SIGNALLING]. DEPENDING
- ON WHERE YOU ARE IN THE COUNTRY, THE
- CALL WOULD LEAVE YOUR TOLL CENTRE
- (ON MORE TRUNKS) TO ANOTHER TOLL
- CENTRE, OR OFFICE OF HIGHER "RANK".
- THEN IT WOULD BE ROUTED TO CENTRAL
- OFFICE 806-258 EVENTUALLY AND THE
- CALL WOULD BE COMPLETED. ILLUSTRATION:
-
- A---CO1-------TC1------TC2----CO2----B
-
- A=YOU CO1=YOUR CENTRAL OFFICE
- TC1=YOUR TOLL OFFICE.
- TC2=TOLL OFFICE IN AMARILLO.
- CO2=806-258 CENTRAL OFFICE.
- B=YOUR FRIEND (806-258-1234)
-
- IN THIS SITUATION IT WOULD BE
- REALISTIC TO SAY THAT CO2 USES SF
- IN-BAND (2600HZ) SIGNALLING, WHILE
- ALL THE OTHERS USE OUT-OF-BAND
- SIGNALLING (3700HZ). IF YOU DON'T
- UNDERSTAND THIS, DON'T WORRY TOO MUCH.
- I AM POINTING THIS OUT MERELY FOR THE
- SAKE OF ACCURACY. THE POINT IS THAT
- WHILE YOU ARE CONNECTED TO 806-258-
- 1234, ALL THOSE TRUNKS FROM YOUR
- CENTRAL OFFICE (CO1) TO THE 806-258
- CENTRAL OFFICE (CO2) DO *NOT* HAVE
- 2600HZ ON THEM, INDICATING TO THE
- BELL EQUIPMENT THAT A CALL IS IN
- PROGRESS AND THE TRUNKS ARE IN USE.
- NOW LET'S SAY YOU'RE TIRED OF
- TALKING TO YOUR FRIEND IN AMARILLO
- (806-258-1234) SO YOU SEND A 2600HZ
- DOWN THE LINE. THIS TONE TRAVELS DOWN
-
- OFFICE (CO2) WHERE IT IS DETECTED.
- HOWEVER, THAT CO THINKS THAT THE
- 2600HZ IS ORIGINATING FROM BELL
- EQUIPMENT, INDICATING TO IT THAT
- YOU'VE HUNG UP, AND THUS THE TRUNKS
- ARE ONCE AGAIN IDLE (WITH 2600HZ
- PRESENT ON THEM). BUT ACTUALLY, YOU
- HAVE NOT HUNG UP, YOU HAVE FOOLED THE
- EQUIPMENT AT YOUR FRIEND'S CO INTO
- THINKING YOU HAVE. THUS,IT DISCONNECTS
- HIM AND RESETS THE EQUIPMENT TO
- PREPARE FOR THE NEXT CALL. ALL THIS
- HAPPENS VERY QUICKLY (300-800MS FOR
- STEP-BY-STEP EQUIPMENT AND 150-400MS
- FOR OTHER EQUIPMENT).
- WHEN YOU STOP SENDING 2600HZ (AFTER
- ABOUT A SECOND), THE EQUIPMENT THINKS
- THAT ANOTHER CALL IS COMING TOWARDS
- IT (I.E., IT THINKS THE FAR END HAS
- COME "OFF-HOOK" SINCE THE TONE HAS
- STOPPED). IT COULD BE THOUGHT OF AS A
- TOGGLE SWITCH: TONE --> ON HOOK, NO
- TONE -->OFF HOOK. NOW THAT YOU'VE
- STOPPED SENDING 2600HZ, SEVERAL THINGS
- HAPPEN:
- 1) A TRUNK IS SEIZED.
-
- 2) A "WINK" IS SENT TO THE CALLING END
- FROM THE CALLED END INDICATING THAT
- THE CALLED END (TRUNK) IS NOT READY TO
- RECEIVE DIGITS YET.
-
- 3) A REGISTER IS FOUND AND ATTACHED
- TO THE CALLED END OF THE TRUNK WITHIN
- ABOUT TWO SECONDS (MAX).
-
- 4) A START-DIAL SIGNAL IS SENT TO THE
- CALLING END FROM THE CALLED END
- INDICATING THAT THE CALLED END IS
-
-
- NOW, ALL OF THIS IS PRETTY MUCH
- TRANSPARENT TO THE BLUE BOXER. ALL HE
- REALLY HEARS WHEN THESE FOUR THINGS
- HAPPEN IS A <BEEP><KERCHUNK>. SO,
- SEIZURE OF A TRUNK WOULD GO SOMETHING
- LIKE THIS:
-
- 1> SEND A 2600HZ
- 2> TERMINATE 2600HZ AFTER 1-2 SECS.
- 3> [BEEP][KERCHUNK]
-
- ONCE THIS HAPPENS, YOU ARE CONNECTED
- TO A TANDEM THAT IS READY TO OBEY YOUR
- EVERY COMMAND. THE NEXT STEP IS TO
- SEND SIGNALLING INFORMATION IN ORDER
- TO PLACE YOUR CALL. FOR THIS YOU MUST
- SIMULATE THE SIGNALLING USED BY
- OPERATORS AND AUTOMATIC TOLL-DIALING
- EQUIPMENT FOR USE ON TRUNKS. THERE
- ARE MAINLY TWO SYSTEMS, DP AND MF.
- HOWEVER, DP WENT OUT WITH THE DINOSAUR
- , SO I'LL ONLY DISCUSS MF SIGNALLING.
- MF (MULTI-FREQUENCY) SIGNALLING IS THE
- SIGNALLING USED BY THE MAJORITY OF THE
- INTER- AND INTRA-LATA NETWORK. IT IS
- ALSO USED IN INTERNATIONAL DIALING
- KNOWN AS THE CCITT NO.5 SYSTEM.
- MF SIGNALLING CONSISTS OF 7 FREQUEN-
- CIES, BEGINNING WITH 700HZ AND
- SEPARATED BY 200HZ. A DIFFERENT SET OF
- TWO OF THE 7 FREQUENCIES REPRESENT THE
- DIGITS 0 THRU 9, PLUS AN ADDITIONAL 5
- SPECIAL KEYS. THE FREQUENCIES AND USES
- ARE AS FOLLOWS:
-
- FREQUENCIES (HZ) DOMESTIC INT'L
- --------------------------------------
- 700+900 1 1
- 900+1100 3 3
- 700+1300 4 4
- 900+1300 5 5
- 1100+1300 6 6
- 700+1500 7 7
- 900+1500 8 8
- 1100+1500 9 9
- 1300+1500 0 0
-
- 700+1700 ST3P CODE 11
- 900+1700 STP CODE 12
- 1100+1700 KP KP1
- 1300+1700 ST2P KP2
- 1500+1700 ST ST
-
- THE TIMING OF ALL THE MF SIGNALS IS
- A NOMINAL 60MS, EXCEPT FOR KP,120MS
-
- DOWNLOADED FROM P-80 SYSTEMS 304-744-2253
-