T-Comfort Comfort Pro S, Руководство по монтажу и пусконаладке

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PBX Networking Connections
Example of a PBX network
Various line types and transmission protocols can be used for point-to-point connections. The required
network topology (distance, connection capacity) determines which type of point-to-point connection is most
suitable.
A Q.SIG-IP network connection can be established using a fast VPN connection. When the connection is via
internet, encryption is advisable for security reasons.
Protocol: Q.SIG or DSS1
The Q.SIG protocol, designed for ISDN point-to-point connections, is the preferable 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 implements the features designed
for ISDN.
N
Note: All layers of the Q.SIG-IP protocol are symmetrical. The following are
unnecessary: a Master/Slave setting, clock and synchronisation settings (please refer
to Connection via Q.SIG.IP starting on page 123).
Point-to-point
connection
Trunk line
PBX PBX PBX PBX
PBX