ZyXEL Communications 2 Plus User Manual

Chapter 8 WAN Screens

ZyWALL 2 Plus User’s Guide

For regular telephone lines, the default Dial string tells the modem that the line uses tone 
dialing. ATDT is the command for a switch that requires tone dialing. If your switch requires 

pulse dialing, change the string to ATDP.
For ISDN lines, there are many more protocols and operational modes. Please consult the 
documentation of your TA. You may need additional commands in both Dial and Init strings. 

The majority of WAN devices default to hanging up the current call when the DTR (Data 
Terminal Ready) signal is dropped by the DTE. When the Drop DTR When Hang Up check 
box is selected, the ZyWALL uses this hardware signal to force the WAN device to hang up, in 
addition to issuing the drop command ATH.

Enable Multicast

Select this check box to turn on IGMP (Internet Group Multicast Protocol). IGMP 

is a network-layer protocol used to establish membership in a Multicast group - it 

is not used to carry user data. 

Multicast Version

Select IGMP-v1 or IGMP-v2. IGMP version 2 (RFC 2236) is an improvement 

over version 1 (RFC 1112) but IGMP version 1 is still in wide use. If you would 

like to read more detailed information about interoperability between IGMP 

version 2 and version 1, please see sections 4 and 5 of RFC 2236. 

Budget

Always On

Select this check box to have the dial backup connection on all of the time. 

Configure Budget

Select this check box to have the dial backup connection on during the time that 

you select. 

Allocated Budget

Type the amount of time (in minutes) that the dial backup connection can be 

used during the time configured in the Period field. Set an amount that is less 

than the time period configured in the Period field. 

Period

Type the time period (in hours) for how often the budget should be reset. For 

example, to allow calls to this remote node for a maximum of 10 minutes every 

hour, set the Allocated Budget to 10 (minutes) and the Period to 1 (hour).

Idle Timeout

Type the number of seconds of idle time (when there is no traffic from the 

ZyWALL to the remote node) for the ZyWALL to wait before it automatically 

disconnects the dial backup connection. This option applies only when the 

ZyWALL initiates the call. The dial backup connection never times out if you set 

this field to "0" (it is the same as selecting Always On).

Apply

Click Apply to save your changes back to the ZyWALL.

Reset

Click Reset to begin configuring this screen afresh.

Table 36   NETWORK > WAN > Dial Backup (continued)