After making a connection, switch off modem


Hello All
Can anyone help here?
If I make a GPRS connection in data mode with A Fasttrack Supreme modem using the WIPsoft commands to a server written in VB6, if I power off modem during a connection, the VB winsock control does not know we have lost the connection. Does any one know why? For example if I telnet our server and close the session, the winsock control knows that the connection is closed, and the session can be terminated. Fine.
But with the GPRS transparent data connection, if modem power is lost, the winsock control does not know. why is this?
Thanks for any replies.


That’s because part of the “closing the session” process is tonotify the server!

If you just pulled the power on the PC with the Telnet client, you would probably see similar behaviour!


Makes sense. I will have to put some polling in for this eventuality.
Thanks for the Reply,



I’m not a VB (or Winsock) expert, but it sounds like the VB system is not getting a ‘Socket Closed’ event of some sort. I would suspect that there should be some sort of timeout to indicate that the socket has gone away prematurely.

Maybe look at setting a timer on the VB code that is reset every time the socket receives data. If the timer times out, assume that the connection has gone away and manually force the connection to close in VB.

ciao, Dave