Page 58
VoIP gateway IP400 version 5.01
5.2.4 Use as a subscriber to an ISDN-PBX
In certain cases, it might be necessary to connect the gateway as a subscriber to
a terminal connection (and therefore also to a point-to-multipoint connection) of
the ISDN-PBX. This is necessary, for example, if the PBX does not support an addi-
tional exchange line, the existing one is to be operated unchanged, and no tie line
is available either (see section 5.2.5 “Use on a PBX tie line” from page 59).
Remember, that in this case various limitations must be expected (depending on
the PBX), since it expects a single terminal on this connection and not a piece of
switching terminal equipment.
This type of connection only occurs in connection with BRI interfaces and is thus
usually only relevant for the IP 400.
In this case, the PBX is connected to the gateway in the same way as an exchange
line, as described in section 5.2.1 “Usage at a public exchange line (dial-up or
permanent connection)” from page 51. The connection provided by the PBX
however is usually a “point-to-multipoint” connection. The
Point to Point
box
should be unchecked accordingly. Check the
Disable overlap receive
box, if the
PBX does not support single digit dialling to the terminal (see section “Single digit
dialling on terminals on point-to-multipoint connections” from page 50).
Fig. 14 Gateway on PBX subscriber interface
ISDN
PBX
BRI subscriber
interface
tel1, tel2 or PPP
Gateway