Sms-Rcs Signaling Functions - Nortel DMS-100 Series Maintenance Manual

3-6 SMS signaling
The DMS–X message header is the first six bytes as follows:
The number of bytes in the actual message or data varies. The CRC
occupies two bytes and detects transmission errors. The end of message
occupies one byte.
Nailed-up cross-connections
To support applications that require special-service cards, a nailed-up
cross-connection is set up and maintained through software. A nailed-up
cross connection is also called a hairpin connection. This connection is a
peripheral-side (P-side) cross-connection. All information flows from an
RCS to the SMS.
The system switches information from the SMS to a DS-1 line. This line
leads to a second RCS or other piece of digital equipment. The information
is not switched through the network.

SMS-RCS signaling functions

A- and B-bit messaging
A- and B-bit messaging supports the subscriber services that the following
sections describe.
Plain ordinary telephone service (POTS) Plain ordinary telephone
service is provided for both single-party and multiparty. Multiparty includes
two-party automatic number identification (ANI) and operator number
identification (ONI) and four- or eight-party ONI.
Coin features Coin first (CCF) and dial tone first (CDF) are provided as
coin features.
297-8231-550 Standard 09.01 August 1998
The first byte is the start of message.
The second byte is the destination task identification (ID) of the
message. An outgoing message uses this ID to identify the process to
receive the message.
The third byte is the source task ID. An incoming message uses this ID
to identify the process that sent the message.
The last three bytes are the task ID number.