Nortel DMS-100 Series Maintenance Manual page 87

DS-1 frame format
Voice channel 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Channel frame
Ft frame 1 Fs frame 2 Ft frame 3 Fs frame 4
Fs= frame signaling bit
Ft = frame timing bit
Message channels
The LCM message channels occupy channel 1 on each of the primary DS-1
links to the host. The remote maintenance module (RMM) requires two
message channels to the host LTC+. These channels occupy channel 2 on
each of the primary links.
The system first sends messages from the CC to the RLCM-EDC to the host
LTC+. The LTC+ recognizes the message is for the P-side node. The LTC+
uses the XPM messaging software system to send the message to a specified
destination through a message channel between the two nodes.
The XPM messaging software system consists of the following functional
layers:
Voice channel 2
The physical link layer (level 1) provides the mechanism required to
transfer the data bits from one node to another node. The DS-1 link that
connects between the host LTC+ P-side interface card and the LTC+
C-side interface card is the necessary mechanism.
185 186 187 188 189 190 191 192 193
Channel frame
Superframe
DMS-100 Family Maintenance Manual ABSK007
Signaling for RLCM-EDC 2-3
Voice channel 24
Fs frame 12
Framing
bit