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Description
553-3001-105
Standard 5.00
June 1999
SL-1 Network loop signaling
SL-1 Network loop signaling is used to send
messages to and receive messages from the peripheral equipment cards. A
typical message to the PE card directs the card to enable the front panel fault
LED, enable ringing onto a particular line, or light the message waiting lamp
for a particular line. A typical message from the PE card tells the system
processor that a line has gone off hook.
Messages are sent and received during timeslot zero. An enable signal TS0
(timeslot zero enable) is generated during each timeslot zero. When the
network card has a message for a particular peripheral card, it asserts the card
enable signal for that card along with the TS0 signal. This continues on
successive TS0s until a complete message has been sent.
The network card regularly polls the PE cards during TS0 to see if any of
them has a message to be sent. When a PE card has a message waiting, it
responds to the poll by sending a series of ones during the next five successive
timeslot zeros. The network card responds by sending a “message send
enable” message (all 1s). The PE card replies by sending 1, 1, 1, 0, and then
the message in successive timeslot zeros.
Summary of Contents for NT1R20
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Page 12: ...xii Contents 553 3001 105 Standard 5 00 June 1999 ...
Page 76: ...Page 52 of 290 Description 553 3001 105 Standard 5 00 June 1999 ...
Page 154: ...Page 130 of 290 NT5D11 Line side T1 Interface Card 553 3001 105 Standard 5 00 June 1999 ...
Page 276: ...Page 252 of 290 QPC452 Basic 500 2500 Analog Line Card 553 3001 105 Standard 5 00 June 1999 ...
Page 306: ...Page 282 of 290 List of terms 553 3001 105 Standard 5 00 June 1999 ...
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