RAS Tab

Use this tab configure parameters of the RAS Interface. Users must also configure the Ethernet tab.

The RAS Interface opens a socket connection with a RAS device. A RAS device is a server of modems available through TCP/IP, waiting for socket connections on an IP port. For each connection accepted on this port, users have access to one modem.

When connecting to a RAS device, first the I/O InterfaceIOKit connects to the socket on the IP address and port configured on the Ethernet tab. After opening the socket, the following initialization or connection steps are performed:

1.Clear the socket (remove any TELNET greeting message received from the RAS device).

2.Send an AT dial message (in ASCII) in the socket.

3.Wait for a CONNECT reply.

4.If the time-out expires, the connection is aborted.

5.If the CONNECT reply is received within the time-out, the socket is available for communication with the device (connection was established).

If step 5 is successful, then the socket behaves as a normal socket, with the RAS device working as a router between the Driver and the device. Bytes sent by the Driver are received by the RAS device and sent to the destination device using a modem. Bytes received by the modem's RAS device are sent back to the Driver using the same socket.

After establishing the connection, the RAS interface monitors data received by the Driver. If a String "NO CARRIER" is found, the socket is closed. If the RAS device does not send a NO CARRIER signal, the RAS Interface cannot detect when the modem connection between the RAS device and the final I/O device fails. To recover from this failure, users are strongly advised to enable the Disconnect if non-responsive option on Setup tab.

RAS tab

Available options on RAS tab