# Modem Configuration

On some devices, you can configure a dial back-up interface to the Untrust zone. You can connect an external modem to the RS-232 serial port to allow the device to have a dial-up backup interface to the Untrust zone. The serial interface is used if there is a failure on the connection through the primary, Ethernet interface to the Untrust zone.

You configure the device to automatically dial to an ISP account when failover to the serial interface occurs. You can configure up to four modem settings.

### To Configure Modem Settings

1. On the Interface (Modem) page, enter the necessary information:

Modem Name: Enter a name to identify the modem.

Init String: Enter the initialization string for the modem.

Status: Select to activate the current modem settings. Only one modem configuration can be active at a time.

Active Modem Setting –

Retry Number: Enter the number of times that ScreenOS retries the dial-up connection if the line is busy or there is no response.

Retry Interval: Enter the interval, in seconds, between dial-up retries.

Inactivity Timeout: Enter the amount of time, in minutes, that the modem can be idle before ScreenOS disconnects the modem.

Interface Speed: From the scrolling list, select the baud rate for the dial-up connection.

2. Click OK to save the settings. Click Apply to continue configuring a modem.

## Modem List

On the Interface (Modem) page, you can all configured modems. The table contains the following information:

Modem: Indicates a name that identifies the modem.

Init-String: Indicates the initialization string for the modem.

Active: Indicates whether the modem setting is active. Only one modem configuration can be active at a time.

Configure: Click Edit to modify the modem configuration, or click Remove to delete it.