User`s guide

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Answering V.120 Calls
V.120 is a protocol designed to provide high-speed point-to-point communication over
ISDN. It provides rate adaptation and can optionally provide error control. Both the calling
and called units must be configured to use V.120 before data can be transferred. Similarly,
if one unit is configured to use the error control facility, the other must be configured in the
same way.
Initial Set Up
Before using V.120 you must first bind one of the two available V.120 instances to the
required ASY port using the Configuration - Network > Interfaces > Serial > Protocol
Bindings page or by using the bind command from the command line, for example:
bind v120 0 asy 0
You should also select the appropriate method of flow control for the ASY port using the
Configuration - Network > Interfaces > Serial > Serial Port n page or by using the
AT&K command from the command line. Other ASY port options such as command echo,
result code format, etc. should also be configured as necessary.
Initiating a V.120 Call
Once the initial configuration is complete, V.120 calls may be initiated using the appropriate
ATD command. For example:
atd01234567890
A successful connection will be indicated by a CONNECT result code being issued to the ASY
port and the unit will switch into on-line mode. In this mode, all data from the terminal
attached to the bound ASY port will be passed transparently through the unit across the
ISDN network to the remote system. Similarly, all data from the remote system will be
passed directly to the terminal attached to the bound ASY port.
If a V.120 call fails the unit will issue the NO ANSWER or NO CARRIER result code to the
ASY port and remain in command mode.
The ATD command may also be used to route a call to an ISDN sub-address by following
the telephone number with the letter S and the required sub-address value. For example:
atd01234567890s003
In this case, the remote system will only answer the call if it has been configured to accept
incoming calls on the specified sub-address.
Answering V.120 Calls
V.120 answering can be enabled from the command interface by setting register S0 for the
appropriate ASY port to a non-zero value. For example:
ats0=1
You should ensure that you have set S0 for the correct ASY port by either entering it
directly on that port or by using the AT\PORT command to select the correct port first.
The actual value used for the parameter sets the number of rings the unit will wait before
answering.