Polycom VSX Series Administrator's Manual page 179

Symptom
Error message occurs
when placing an ISDN
(H.230) call.
The PBX does not accept
calls of type "unknown"
from the PRI network
interface module.
Cannot complete calls to
sites that do not use
encryption.
A system using a
V.35/RS-449/RS-530
interface cannot receive
calls at certain speeds.
Cannot dial remote
system in bonding 384 K
calls. (The call progress
circles only show blue or
yellow.)
© Polycom, Inc.
Problem
An ISDN cause code is
received from the ISDN
line.
The highest-numbered
channel did not connect.
The system cannot make a
call if this channel does not
connect.
The ISDN switch type is
not configured correctly on
the VSX system.
The network interface
module is not connected
properly.
The PRI network interface
is not configured correctly.
The system displays a
message stating that
encryption is required.
V.35/RS-449/RS-530
systems cannot determine
how to allocate bandwidth
for call speeds that are
divisible by both 56 and 64
(such as 448K: 8 x 56K),
so the call cannot be
connected correctly.
Switch protocol issue.
Chapter 7 - Diagnostics and General Troubleshooting
Corrective action
Try the call again.
For more information, please refer to
on page Appendix-6.
Be sure you are calling the correct number. The number
may need to include:
• A digit for an outside line
• A long distance access code
• An international access code
• A country code
• An area code or city code
Check that all network cables are properly connected.
Power off the system, wait five seconds, and power on the
system. Then wait about two minutes to allow the ISDN
lines to resynchronize.
Ask the person at the far site to call your system.
Check the ISDN configuration and verify with your ISDN
service provider that the system is configured correctly.
Check the cables to the network interface module.
Verify that you have configured the system's PRI network
interface correctly. For detailed instructions, see
Configuring the PRI Network Interface on page
Your system is configured to require all calls to be
encrypted, and encryption is not available at the far site.
Call the far site, or have the caller try again at a different
call speed.
Start by calling the far site at 1x56, 1x64, 2x56, or 2x64K,
as appropriate. This will verify the primary number. If
these calls complete, try 256K, then 384K.
Being able to dial non-bonded but unable to dial bonded
to all locations is usually a switch protocol issue. Verify
your ISDN provisioning with the telephone service
provider.
Q.850 Cause Codes
3-16.
7 - 15