Instruction manual

Page 1106 of 3156 CLASS: Calling Number and Name Delivery
553-3001-306 Standard 10.00 January 2002
CLASS feature operation
A call originated from Set A (or trunk A) seeks to terminate on a CLASS
set B. When B starts to ring, A will hear ringback. A unit in CMOD (CLASS
Modem) is assigned to collect originator’s CND information and waits for the
CND delivery interval. After the first ring at B, a silence period (deliver
interval) ensues, the CMOD unit begins to deliver CND information to the
CLASS set.
The CND information of a traffic source (A) is a system information, which
is obtained by the system when a call is originated. During the two-second
ringing period of the CLASS set B, A’s CND is delivered to CMOD via SSD
messages (using a signaling channel only). When the CND information is
sent from CMOD to CLASS set B, it is delivered through a voice path during
the four-second silence cycle of set B. The CMOD unit is held for a duration
of six seconds.
If the XCMC (Extended CLASS Modem Card) IPE pack, which provides up
to 32 CMOD units, is located in the IPE of Group 0, the CMOD unit in the
pack will receive CND data through the SSD messages and use one of the
voice channels of the inter-group junctor to deliver it to CLASS set B in
Group 1.
If the XCMC IPE pack is located in Group 1, the system will deliver SSD
messages containing CND information to CMOD and then send it to Set B
during the delivery interval through a voice path, which is an intra-group
channel not involving an inter-group junctor.
When CMOD units and CLASS sets are co-located in the same network
group, there are no voice paths on the inter-group junctor required to deliver
CND information; when they are equipped on different groups, inter-group
junctors must carry CND traffic. The resource allocation algorithm will
search for a CMOD unit located in the same group as the terminating CLASS
set first before it attempts to use a CMOD unit from a different group.
Inter-group junctor capacity
The time slot allocation algorithm for inter-group junctors is somewhat
different from regular network loops, however, it is a close approximation to
use the network loop capacity for junctor capacity, since they each have 30
traffic channels.