Automatically cancel incoming call to modem without answering AT+CHUP call?

Question

PHP

I'm using a USB modem to send faxes/data over a regular voice channel.
1) I turn on the caller ID:
> AT+CLIP=1\r
2) I'm waiting for a call:
< RING
< +CLIP: "[phone]",145,,,,0
3) I see that the number is "left" (that is, not a modem and not a fax, but a regular phone), I want to hang up:
> ATH \ r
4) the modem answers “OK”, but the call does not reset (
< OK
Question: is it really possible to reject a call, you must first “pick up the phone” with the “ATA” command ” and then “hang up” with the “ATH” command (as was the case on ancient “dial” phones), instead of just “press-red-call-cancel-button” (as is done on modern “cell” phones)?

Answer 1

Can give a busy signal (BUSY)?

Answer 2

If a voice channel means a regular telephone line, then there is no full-fledged subscriber signaling (such as in mobile phones). Therefore, it is really necessary to first initiate a response, and after some small interval (anti-bounce?) - hang up.

Answer 3

Thanks a lot!
AT+CHUP\r is exactly what I needed!

Answer 4

And what modem do you use and what operator and what program?
I have E173 and Megafon and Venta Fax
Voice calls go through, but no fax.