User guide

Help Contents > Getting Started with the ISDN gateway > Using the ISDN gateway for Voice-Only Calls
Using the ISDN gateway for Voice-Only Calls
The ISDN gateway can be used to forward voice-only IP calls to the ISDN network (the PSTN); likewise, it can be used to
forward voice-only ISDN calls from the PSTN to IP telephones on the IP network. If you want to use the ISDN gateway to
forward voice-only calls, there are two ways to configure this feature:
● globally:
either
❍ entirely as a voice-only gateway: where all IP calls and all ISDN calls are forwarded as voice-only
calls
or
❍ partly as a voice-only gateway: where incoming ISDN video-conferencing calls are allowed, but
outgoing ISDN calls are voice only (or vice-versa)
● dial plan configuration: where particular calls (ingoing and outgoing) are allowed to be video-conferencing
calls, and where particular calls are restricted to voice-only
IP to ISDN calls: IP endpoints sometimes do not allow the caller to specify the type of call being made. For example, a
caller may want to make a telephone call (that is, voice only), but are unable to specify that this is a telephone call. To
overcome this problem, for IP data calls, if required, the ISDN gateway can extract the voice part of the call and forward
it to the ISDN network as a voice-only call. For IP to ISDN calls, if the ISDN gateway receives a video-conferencing call
that has been restricted to being a voice-only call (due to the settings on the ISDN gateway), the unit will forward it as a
voice-only call (the call will not be dropped). If the IP endpoint does allow call type to be specified, an IP telephone call
will always be placed as such.
ISDN to IP calls: ISDN endpoints usually allow a caller to specify the type of call being made. This is important,
because with ISDN calls the voice part of the call cannot be separated from the video part. Therefore, if the ISDN
gateway receives a video-conferencing call and the dial plan restricts the ISDN gateway to voice-only calls, the unit will
drop the call. Voice-only telephone calls will always be accepted by the ISDN gateway.
Configuring the ISDN gateway as a Voice-Only Gateway
1. Go to Home > Settings > ISDN.
❍ To configure the ISDN gateway to restrict incoming ISDN calls to voice-only calls, set the Max
outgoing ISDN call rate to Telephone.
❍ To configure the ISDN gateway to restrict outgoing ISDN calls to voice-only calls, set the Max
outgoing ISDN call rate to Telephone.
2. Complete the other ISDN settings as per your requirements. For more information about the ISDN settings
page, refer to
Configuring General ISDN Settings.
Note: You can set both the incoming and outgoing maximum call rates to Telephone to use the ISDN gateway entirely
as a voice-only gateway.
Dial Plan Configuration
You can configure the dial plan to restrict particular called numbers to voice-only calls. In this way, you can configure the
ISDN gateway to allow particular outgoing/incoming ISDN calls to be video-conferencing calls. Using the dial plan
therefore allows you greater flexibility (if you need it) than using the global settings on the ISDN settings page.
For more information about configuring the dial plan, refer to
Understanding the Dial Plan, Adding and Updating Dial Plan
Rules, and Example Dial Plan Rules.
Calling a PSTN Telephone from an MCU
If you want to call someone on a regular land-line telephone into a conference on the MCU, you must add the ISDN
gateway as a participant, using one of the following methods:
● specifiy it as a gateway with an extension.
● call a particular number registered to a common gatekeeper.
● call the ISDN gateway by IP and let the ISDN gateway itself work out which number to call based on dial plan
rules.
Whichever method you use, you must have a dial plan configured, such that a rule is invoked that has "Telephone"
bandwidth, specified for the call. Then the call will be established correctly.
Codian ISDN GW 3200 Series User Guide Version 1.0(1.18)
Copyright (c) Codian Limited, 2006 Page 9 of 50