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modem doesn't answer

© December 2004 Tony Lawrence

(Mostly SCO related)

A modem that doesn't answer at all may not have any getty running on it to assert DTR. If you don't see DTR, it isn't going to answer. Power cycle the modem, disable the tty port, reenable it. Don't have both the modem and non-modem ports enabled: disable tty1a, enable tty1A. On systems very prone to losing this, I'll even have a cron job that does this periodically; it won't interfere with an existing connection (the disable will fail).

NO CARRIER usually means what it says: no dial tone. Modems need working phone lines.

Don't use internal modems with Unix/Linux systems:

You can get more details on the actual conversation between modems (or lack of conversation) by using "cu -x9" on systems that use cu (which turns on diagnostic output). Or use "uutry -x9" with a system name on systems with uucp.

On any old system, use Kermit.

The SCO modem manager doesn't work very well; see High speed modem setup for the manual methods. The secret is forcing both the modem and the serial port it is attached to set to run at a the same fixed baud rate.

Related: What are some common settings for my modem?
RS232 Wiring Diagrams
I have a modem directly connected to a WY-60 terminal, but I don't get any display of AT commands on the screen.

Got something to add? Send me email.

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-> modem doesn't answer ––>Re: cu and uucp

Inexpensive and informative Apple related e-books:

Photos for Mac: A Take Control Crash Course

Digital Sharing Crash Course

Take Control of High Sierra

Take Control of Pages

Take Control of OS X Server

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