Connections; Protocol: Q.sig Or Dss1 - Aastra OpenCom 100 Mounting And Commissioning User Manual

PBX Networking
12.1

Connections

Networking two or more TK systems means interconnecting them. The
OpenCom 100 allows you to use the following connections:
■
ISDN trunk lines
■
ISDN point-to-point connections (Q.SIG) on external S
■
IP network connections (Q.SIG-IP)
PBX PBX PBX
PBX
Example of a PBX network
Various line types and transmission protocols can be used for point-to-point con-
nections. The required network topology (distance, connection capacity) deter-
mines which type of point-to-point connection is most suitable.

12.1.1 Protocol: Q.SIG or DSS1

The Q.SIG protocol, designed for ISDN point-to-point connections, is the pref-
erable choice as the transmission protocol; alternatively, the DSS1 protocol,
designed for ISDN dial-up connections in the Euro-ISDN, can be used. Certain PBX
networking features can only be used with the Q.SIG/Q.SIG-IP protocol, however.
In particular, the identifier indicating whether a call is internal or external cannot
be transmitted using DSS1.
Both protocols implement communication on several protocol layers:
■
L1: Layer 1 defines the physical line properties and the electrical coding of
signals.
■
L2: Layer 2 enables communication via individual error-protected channels
that are independent of each other.
■
L3: Layer 3 defines the administration of the individual channels and imple-
ments the features designed for ISDN.
154
PBX
Trunk line
Point-to-point
connection
Connections
ports or on the S
0 2M
port