Nortel DMS-100 Series Maintenance Manual page 40

1-24 Maintenance overview
The UP collects the return signaling information from the RCS. This
information includes the following data:
The RCS never sends the modulated 1 and 0 messages to the SMS. The
RCS sends steady 1 and 0 messaging. The SMS can send modulated 1 and 0
to the RCS.
The system decodes A- and B-bit messages in a different way for each type
of RCS line card. For example, a pattern for a single-party line card and the
same pattern for a coin card can have different indications.
The UP contains the A/B-bit facility software section. The A/B-bit facility
makes sure that the 8085 microprocessor operates correctly. The A/B-bit
facility scans incoming RCS signaling information for each channel. The
A/B-bit facility scans each channel for origination, answer, flash, disconnect,
and other subscriber telephone states. The definition for each state follows:
297-8231-550 Standard 09.01 August 1998
start or stop ringing
start or stop forward disconnect
scan for on-hook and off-hook
collect ANI/Coin information
collect channel maintenance information
call origination
call disconnect
digit collection
automatic number identification (ANI)/coin
answer
flash
Origination—subscriber line goes off-hook from on-hook. The
subscriber line stays off-hook for a minimum of 400 ms.
Digit collection—subscriber line pulses 7.5 to 12 times every 1 s, with a
break percentage of 58 to 64%. The digit-to-digit time-out is 300 ms.
Answer (to ringing)—subscriber line goes off-hook from on-hook. The
subscriber line stays off-hook for a minimum of 200 ms.
Flash—subscriber line goes on-hook from off-hook. The subscriber line
stays on-hook for a minimum of 400 ms and maximum of 1550 ms. The
subscriber line returns to the off-hook state for a minimum of 200 ms.