NewDeal Hot Tip 1110

[Hot Tips for...] Telecommunications

Stay Connected While Taskswitching

You can taskswitch out to a DOS program or back to Windows while using NewComm or your Internet clients, without losing connection on most computers using the task switching feature of DR DOS or Windows. What's needed is to set the modem to ignore DTR. Whatever you are doing online is suspended, but when you switch back to NewDeal, everything continues where it left off, provided your connection hasn't timed out.

Of course, you probably will not want to stay out in another program for more than a few minutes at a time if you're connected to a commercial service, since the money meter is still running while you're out there. However, this can be really handy for checking on a feature in another program, or for searching out some information with a word processor that has a search feature, or for gathering some text for pasting into Email.


DTR stands for Data Terminal Ready and refers to the signal that is carried on one of the wires in your serial port connection for an external modem (for an internal modem, the connection is built-in). In order to task switch and not automatically lose your connection, your modem must ignore DTR.

The Hayes command for telling a modem to ignore DTR is:

That's a zero, not the letter o. Some modems default to ignoring the DTR signal. Others default to paying attention to it. And there are a few modems that won't even recognize the command.

Some modems will accept the command AT&D0&W, which will save the &D0 setting in non-volatile RAM within the modem, so that it becomes the default every time you boot up. To use this, enter the command in NewComm, or any DOS terminal program you like. If your modem responds to AT&D0 (not all do, like the Courier HST), then just enter in terminal mode:

Or you can include the command AT&D0 in your intialization string.


For this to work with the taskswitching feature of DR DOS, your modem must be configured for IRQ 3 or IRQ 4. TaskMAX, or DR DOS's taskswitching feature, may not let you exit if a COM port is actively using IRQ 5 or IRQ 7.
Return to Index

Last Modified 2 Mar 1999