Remote Computing/Modem Tip

I spend quite a bit of my time logged on to HP3000s via modem. Over the years I have learned many tips and tricks to remote computing and I would like to share one of them with you.

Disconnecting the phone line sounds like a simple enough task but sometimes can be quite difficult. Under normal operating conditions when you type in BYE the modems will disconnect automatically. Some systems are not set up correctly to disconnect the phone line (which by the way can be a serious security risk,) so after logging off you must disconnect the phone line manually. There are several ways to accomplish this.

With an external modem you can simply turn the modem off to disconnect the phone line. You can accomplish the same thing with a PC and an internal modem by turning off the PC but you may have to save your work in other applications first and don’t necessarily want to reboot just to disconnect the phone line.

My favorite, if you are running Reflection on a PC, is to press ALT-Y to bring up the Reflection command line or command window and type in DISCONNECT. This will cause the modem to momentarily drop Data Terminal Ready and disconnect the phone line.

Another method is to return the modem to command mode and the give it the disconnect command. To return from online mode to command mode you must give the modem at least one second of “silence” (no data), then three plus signs (+++) by typing them on the keyboard and then another second of silence. (The reason for the silence and the plus signs is so that the modem will not mistake a “+++” in the middle of a stream of data for the escape sequence.) If it has accepted the escape sequence the modem will respond with OK. You can then tell the modem to hang up with the command ATHO (zero).