Escape to Command Mode (+++)

Escape to Command Mode (Updated 13-May-03)

Modems have a way to drop into command mode without disconnecting. In some cases, you might want to do this - as in testing your modem with HyperTerminal.

Command mode is entered if the modem receives the proper escape code. Nearly all modems default to using an escape code of 3 plus signs: +++

In order to prevent the modem from entering command mode - which stops data transmission - with normal data, the escape code must be surrounded by an interval during which no data is sent - the guard time. Most modems have a default value of 1 second for the guard time: unless there is a 1-second pause before and after the +++, the modem will not go into command mode.

Some modems may not obey their own rules regarding escape code, or in unusual cases, the datastream may actually contain a valid escape code.

Most modems allow you to disable the escape code by setting s2=255. Additionally, most modems will allow you to set the duration (in 50th's of a second) of the guard time with s12=##.

If you are unable to send certain things - perhaps a large e-mail - without data stopping or disconnection, your fix may be to disable the escape code or increase the guard time.

In most cases, you'll want to avoid placing the modem in command mode while you are online; however, Franc Zabkar found a way to use the escape code to improve a connection by forcing a retrain - see his comp.dcom.modems post.