Operation Manual

Configuring ISDN Interfaces 113
4. If you are using an AVM ISDN-Controller for PRI, check the
CRC4 Multiframe Format .
Default: Enabled
Options: Enabled, Disabled
In some countries, there are two different types of PRI switching
stations which use different signalling formats on the D channel.
Newer stations use CRC4 Multiframe format, older ones
Doubleframe format. Call set-up problems may be the result,
which become apparent through the following: The D channel
LED on the AVM ISDN-Controller T1/T1-B flashes and the ISDN
network returns the error message 3301 or 3302.
In such a case, ask your local PTT if CRC4 Multiframe is sup-
ported at your local switching station. If not, you should disable
CRC4 Multiframe Format in this menu.
5. Press <Esc> to return to the ISDN Network Interface Con-
figuration menu.
When you are finished, press <Esc> twice, select Yes to save your
changes to the Interface Configuration, then press <Enter>.
The Network Interfaces menu reappears.
To configure the remaining interfaces, if any, repeat the steps de-
scribed in the sections "ISDN Network Interface Configuration",
"Expert Configuration for ISDN Interface <Name>" and "Default
Interface Call Destination" above.
Then, proceed to Chapter 7, "Configuring ISDN-Call Destinations" to
configure your call destinations.