I'm looking for something like this.

I need to know how to send an AT command to an external modem through RS232. In fact I need to set the modem to auto answer at the 4th ring. In AT commands it means "ATS0=4" (in something like HyperTerminal). I've tried to send the ASCII commands of the sequence individually, but it failed. I'm thinking that is a problem with the serial port configuration. Here's a copy of the routine that do it:

ORG 00H
MOV SCON,#010H
MOV A,#07FH
ANL A,87h
MOV 087h,A
MOV SBUF,#041H
MOV SBUF,#054H
MOV SBUF,#053H
MOV SBUF,#030H
MOV SBUF,#03DH
MOV SBUF,#034H

END

thank you anyway.


Thiago Camargo (Brazil)