textfiles/phreak/tandems
2021-04-15 13:31:59 -05:00

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Tandem's
Written By Forest Ranger
The Tandem:
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Each tandem is a line with the capability of signaling any other tandem in
any other toll switching office in North America. Tandems are programmed to
route themselves to other tandems if all other direct routes are busy. If all
other tandems are busy in one area then your tandem will route itself to the
next nearest tandem that may be in another part of the continent.
When a tandem is idle waiting for someone to use it sits there whistling
2600 Cycles per second facing all of thm numbers serviced by that exchange.
This just means that the tandem is ready to be used. The other side of the
the tandem is whistling 2600 cycles per second also into a number of trunk
lines telling the phone system that the tandem has no outgoing or incoming
calls.
Dialing the Tandem:
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You are automatically hooked into a tandem when you dial a long-distance
phone number. The tandem then sends the number you dialed to the side facing
away from you. The senling side stops whistling the 2600 cycles per second
into the trunk line and at this point has been taken over. It will then carry
the number dialed that will be converted to multi-frequency beep tones to a
tandem in the NPA and centeral office you requested.
FROM TARAN KING AT METAL SHOP (314)432-0756