Nortel DMS-100 Series Maintenance Manual page 123

The SMS sends the following signaling information to the RCS on a
per-channel basis:
start or stop ringing
start or stop forward disconnect
scan for on-hook and off-hook
collect ANI/Coin information
collect channel maintenance information
The SMS collects return signaling information from the RCS that includes
the following data:
call origination
call disconnect
digit collection
ANI/coin
answer
flash
A- and B-bit messages are decoded in a different way for each type of RCS
line card. An example of this condition is when a specific pattern for a
single-party line card can indicate a different pattern for a coin card.
Universal tone receiver (UTR) features The RCS lines that connect
an SMS can use the optional UTR feature. This feature removes part of the
processing load from the central control (CC) and implements the load in the
PM.
When the UTR feature is present on the SMS, the SMS performs all digit
collection functions. Digit collection occurs at the originating terminal.
The digit collection functions include:
the allocation of a free receiver
the establishment of a path to the receiver
the collection and processing of digits
the deallocation of the receiver
DMS-100 Family SMS Maintenance Manual XPM10 and up
SMS signaling 3-7