Nortel DMS-100 Series Maintenance Manual page 129

SMS signaling 3-13
Any subsequent DSCWID options on a SCWID or 2500 use a new timer
(T-flash). The system uses T-flash after the subscriber answers a call with
SCWID and 2500 sets. This action provides the customer with enough time
to select an option after a flash. T-flash is a operating company controlled
timer that can be set from 1 to 8 s. The default value is 1.5 s. The SMS
starts the T-flash timer when the NON-ADSI field is set to "Y". The SMS
receives a flash signal from the SCWID or 2500 set of the customer during
the held or conference call state. When the SMS cannot attach a UTR
before 400 ms, the SMS applies the RETURN option.
Note: For Bellcore TR-416 compliance, the SMS must provide options
when the SMS detects a flash and cannot attach a UTR. The SMS sends a
flash to the CC when the SMS cannot attach a UTR in 400 ms. The SMS
initiates this event to make sure that the SMS complies with this
requirement.
Meridian Digital Centrex (MDC) on SMS The SMS-RCS subsystem
supports Integrated Business Network (IBN) features. The SMS does not
support trunks, so that IBN features that require trunks must terminate on
equipment other than an SMS. Station features are limited to 500/2500 sets
and attendant consoles. This limit is present because the SMS does not
support Meridian business sets (MBS) or data units.
DDL messaging
The 8085 microprocessor of the A/B DDL message card also sends DDL
messages. The 8085 microprocessor sends these messages to the time
switch in the DS-1 PCM data stream. The microprocessor extracts the DDL
message from incoming PCM. Software in the SP, called the DDL facility,
processes DDL messages.
The DDL message consists of 24 consecutive bits, grouped as shown in the
"DDL message bits and field names" table.
DMS-100 Family SMS Maintenance Manual XPM10 and up