Software Description - Nortel DMS-100 Series Maintenance Manual

Software description

The following sections describe the software operation of the NTX146AB
feature package.
Interface to DS-1 links
The RLCM-EDC provides an interface between the host controller and up to
640 subscriber lines (140 P-phones in the initial application) through the
DS-1 links. The LCCs reassign data carried over the 32 channels of a
DS30A link to the 24 channels of a corresponding DS-1 link.
LCC control data
When a unit of the RLCM-EDC is to be placed in service (InSv), the LCC
for that unit receives control data from the LCM indicating the number of
DS-1 cards equipped and which clock source is to be used for the
RLCM-EDC. The LCM receives this data, in turn, from the host LTC.
Messages are sent to the LCM unit from the host during its return to service
(RTS), and whenever the CC attempts to switch the LCM clock source from
one LCC to the other.
The LCC clock source, which is frequency-locked to the primary DS-1
links, is controlled by RLCM-EDC software, except when both units of the
LCM are inactive. When this is the case, LCM hardware forces each LCM
unit to take its clock source from its own LCC.
Other host office functions
The following functions are controlled by software resident in the host
DMS-100 Family office:
class of service
code interpretation
screening
routing
billing
Signaling and supervision
Signaling allows the DMS-100 switch to communicate with its stations or
other switching offices. The RLCM-EDC uses HDLC LAP-D protocol to
communicate over its DS-1 links with the host LTC+ for the extended
distance capability application. This protocol is implemented by the
NTMX76BA messaging card, located in the host LTC+, replacing the
NT6X69 card. The same links are used as message links between the LTC+
and the RLCM-EDC, but timeslot 06 is used through the speech bus
interface (SBIF).
Maintenance overview 1-51
DMS-100 Family Maintenance Manual ABSK007