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NDA-24305 CHAPTER 6
Page 185
Revision 1.0
B-CHANNEL SERVICE CONTROL
B-27 B-CHANNEL SERVICE CONTROL
1. General Description
A PBX can send a trunk maintenance (SERVICE) message to the ISDN (AT&T-#4ESS, NT-DMS100/250)
when setting or cancelling a trunk make busy using the MBTK command. This function is not provided by NI-2
protocol.
Whether “In Service” mode or “Out of Service” mode of a PBX is determined by a trunk maintenance message
from the network. (Even if a PBX sent a trunk maintenance message setting the PBX to “Out of Service” mode,
the PBX would be set “In Service” when the PBX receives a trunk maintenance message for “In Service” from
the network.)
<For AT&T>
When a PBX has been set to “Out of Service” mode after receiving a trunk maintenance message from the
network, incoming calls from the network would not be allowed
.
<For NT>
Even if a PBX has been set to “Out of Service” mode after receiving a trunk maintenance message from the
network, incoming calls from the network would be allowed
.
2. Operating Procedure
Using MBTK,
Set make busy to a bothway call (MB=2): A PBX sends a trunk maintenance message.
Cancel the bothway make busy (MB=0): A PBX sends a trunk maintenance message.
3. Programming
None.
Note:
SERV (Service) message = Trunk Maintenance message.
SERV (Service) ACK = Service acknowledgement.
IOC
PRT
SERV ACK
SERV message
NETWORK
(AT&T/NT)