Initial Setup - Digi transport User Manual

Configure ISDN interfaces
Configure ISDN to answer 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
routers must be configured to use V.120 before data can be transferred. Similarly, if one router is
configured to use the error control facility, the other must be configured in the same way.

Initial setup

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 router 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 router 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 router 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.
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