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V.120 outgoing protocol – ZyXEL Communications omni.net Plus User Manual

Page 92

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Technical Reference for ZyXEL omni.net series

8-4

V.120 Outgoing Protocol

Some switches transmit all network signals through the D-channel (out-of-band signaling), allowing both
B-channels to be used exclusively for your communication purposes. This allows for throughput of 64Kbps per
channel. However, not all switches support out-of-band signaling at this time. For switches that do not support
out-of-band signaling, network signals are transmitted through the B-channels. This reduces the bandwidth to
56Kbps.

When you are making a V.120 call, make sure that the communication supports out-of-band signaling. If it
does not support out-of-band signaling, you will need to set your omni.net to 56K mode using the [AT&E1]
command ([AT&E0] to set it back to 64k mode.) If your ISDN TA is on the receiving end, you can keep the
setting at AT&E0, 64k data mode. The omni.net will automatically switch between the two speeds in answer
mode.

Type AT
Command

Description

omni.net Response

ATB20

Select V.120 for communication.

OK

AT&E0

Select 64K data mode.

OK

AT&E1

Select 56K data mode.

OK

Now you are ready to dial the phone number. If you need to save the setting into non-volatile RAM, issue the
following commands:

AT&W0

Save the settings to profile 0

[Profiles available: 0-3]

OK

ATZ0

Save stored settings as the power on
settings to profile 0. [Profiles available:
0-3]

OK

All the above commands can be simplified by combining all of the commands onto one line as follows:
&

AT&B20&E1&WZ0

Finally, use the [ATDIn] command to make the call ('n' is the phone number you wish to dial). Once the
connection is made, you should see the following connect message.

ATDIn

CONNECT 115200/V120 56000/LAPD

This indicates that the connection is made with:

)

DTE speed of 115,200bps.

)

V.120 Protocol

)

Data Speed of 56,000bps.

)

Error Control LAPD.

Table 45. V.120 Outgoing Protocol

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