Keeping A Line Connection During Idle Time - NETGEAR XM128 ISDN Reference Manual

Reference Guide for the Model XM128 ISDN Digital Modem
Most of the time, you only use this protocol for making calls to remote sites with ISDN LAN
Routers. If the remote access site you are calling uses a Terminal Adapter such as the
Model XM128 modem, you can use V.120, as it provides data compression.
Before making the call, check which protocol is set for the ISDN mode using the &V command to
view the settings.
When you are ready to view the settings type:
AT&V<Enter>
The Model XM128 modem modem responds:
Current Settings...
Switch Type: Northern Telecom DMS
ISDN Outgoing Service: PPP Async-to-Sync Conv 64K
If the settings displayed match your current setup, you are ready to place the call.
When you are ready to place the call type:
ATDI<remote_access_number><Enter>
The Model XM128 modem responds:
Connect 115000/64000 PPP/None

Keeping a Line Connection During Idle Time

If you are using PPP to access a server the server probably has a watchdog timer to monitor the
line activity. If the idle time exceeds some time interval (usually 1 minute), the server releases the
connection for other clients to dial in. Users may suffer some inconvenience because you have to
dial to the server again and repeat the login procedure when disconnected. The value in register
S124 (in seconds) is used as the idle time gauge. If the idle time exceeds this guarding period, the
Model XM128 modem sends out a dummy PPP packet to the server to keep it from disconnecting
the line.
Example: If the server you are calling disconnects after 1 minute of inactivity, issue the following
command before connecting:
ATS124=59<Enter> (send dummy PPP packet after 59 seconds of inactivity)
Setting S124=0 disables this function.
5-2 Async to Sync PPP