DETEWE OpenCom 130, User Manual

Page: 130 / 204

PBX Networking Connections
128
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
0
ports or on the S
2M
port
■
IP network connections (Q.SIG-IP)
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 prefe-
rable 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.
Point-to-point
connection
Trunk line
PBX PBX PBX PBX
PBX