Nortel BCM 3.7, Manual

Page: 327 / 1004

Programming access codes 327
Programming Operations Guide
Using the MCDN access codes (tandem calls)
Three special codes exist specifically for programming over PRI and VoIP trunks that are using
the MCDN protocol, and which connect to a call server systems that use specific call codes for
special call types, such as the Meridian 1 (M1). The purpose of the codes is to allow easier
programming of the call server systems when calls are tandemed through a Business
Communications Manager to the local PSTN.
Calls tandeming to the public network through the private network need to retain their dialing
protocol throughout the private network. This means that a call from an M1 node tagged as a local
call gets received by the BCM node and is recognized as a call intended for the public network, but
also as a call that needs to maintain the local call tag until it gets to the BCM node that is directly
connected to the PSTN. This is accomplished by ensuring that the destination code, which starts
with this access code, passes the call on using the route designated with the correct call type. Refer
to
“Defining routes” on page 333 . The following figure charts this process.
Figure 94
Local call tandemed through Business Communications Manager nodes
Local
PSTN
823-2222
Dialout: 9-823-2222
Dialout: <local call>-823-2222
Meridian user
The Meridian system recognizes the call as
a local public call.
Deletes the routing digits.
Tags call as Local call type
Sends out rest of dialout on private network
The Business Communications Manager
Adds Local code to front of called number:
9-823-2222
Dialout: 9-823-2222
The Business Communications Manager
receives the call. The system recognizes
9823 as the destination code for the local
PSTN route. Route drops the leading
digit and dials out over the PSTN trunk.
Dialout: [unknown] 823-2222
The system knows 9823 is the route to the next
system and routes the call through private network.