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ZOC Terminal is a professional SSH Client and Terminal Emulator for Windows and macOS.
ZOC Online Help Topic:

Serial/Modem/Direct → Modem AT Commands for Serial/Modem

This window is used to define the strings ZOC uses to communicate with your modem. These strings may contain control characters (e.g. ^M, see Special Codes), the tilde (~, which is a delay of 1/3 sec) and ^# to be substituted with a phone number.


This is a list of modem commands to set the modem to a defined state before using it. You should be aware that ZOC (unlike some other programs) requires a ^M at the end of the initialization string.

If you do not know what to use for the initialization string, please try either ATZ, AT&F or AT&F1 or check the modem manual for advice

Depending on your setup, you might want to send the initialization string every time you load an options file (e.g. when having different options files for different modem configurations).

Normally ZOC does not send an init sequence if it finds a carrier detect signal from the modem (to prevent a modem reset while you are online). However, some modems provide a CD signal after power on. In this case you should enable this option (and add AT&C1 to the modem init string to tell the modem to provide a real carrier detect signal).

Dial Commands

ZOC lets you set up four dial commands for calling different types of numbers (i.e. using a credit card number to make long distance calls). You can select the dial command to be used from the Host Directory and when dialing manually (from the File Menu).

To dial via modem a comm program has to send a dial command and the phone number to the modem and has to complete this command by sending ^M. The dial commands are ATDT for tone dialing, ATDP for pulse dialing and ATDI for Zyxel ISDN modems. Hence, for the dialing fields you use the appropriate dial command, append the string ^# (which is replaced with the telephone number) and ^M

A standard dial command would look like ATDT^#^M (meaning that ATDT, then the phone number and then enter is sent). If you wanted to set the modem to ignore the dial tone and send a zero before the telephone number to get an outside line, you can use ATX3DT 0,^#^M instead (X3 will prevent the modem from waiting for a dial tone and 0, will send a zero and make a pause before dialing the phone number).

If you want to issue a modem command before dialing you should add some tilde characters between that command and the dial command (as in ATZ^M~~~ATDT ^#^M) to give the modem time to process the former command before continuing to process the latter.


ZOC supports two methods of telling a modem to hang up. Using the DTR signal of the com port is the superior of the two. If you disable it, ZOC will use the ATH command.

Auto answer

Here you supply two modem commands to enable and disable the modem's auto answer mode. These are ATS0=1^M and ATS0=0^M for basically all modems.


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