Owner`s manual

24 MultiMobile
Chapter 3—Application Program Interfaces (APIs)
B-Channel Protocol Configuration
Most ISDN switches transmit network signaling data through the
D-channel, allowing both B-channels to be used exclusively for
communications, which is called out-of-band signaling. This allows for
throughput of 64 Kbps per channel. However, not all ISDN switches
support out-of-band signaling.
For switches that do not support out-of-band signaling, network signaling
data is transmitted through the B-channels. This downgrades B-channel
bandwidth to 56 Kbps for communications use. Before making ISDN calls,
specify the ISDN switches you are connecting to support 56K or 64K
B-channel speed and specify the correct line speed.
In VCOMM mode (V.120, or async-to-sync PPP and Multi-Link mode), use
the AT!Q command or the Configuration Utility to specify the ISDN
B-channel data rate.
AT!Q=0 Select 64 Kbps for B-channel communications
AT!Q=4 Select 56 Kbps for B-channel communications
V.120 Protocol Configuration
When making V.120 calls, make sure the ISDN switch you connect to
supports out-of-band signaling. Otherwise, set 56 Kbps B-channel speed
for communications. For example: Enter AT!Z=5 to set to V.120 mode.
Then, use the ATD or ATDT command to dial ATD5551000 or
ATDT5551000. Or, select the V.120 protocol in the Configuration Utility.