The modem i use is a Creatix V90/56k external modem. Creatix Lifetec GC 326.0 modem
http://www.creatix.com/support/frames.html
V.90 (external)

1) Can you write a batch file that would stop and wait for you to enter multiple characters from keyboard until pressing ENTER key and take conditional action? (I don't think you can.) If you can't do that with a batch file, I don't think there's anyway you can go further.

2) If you can do (1) above, then you'd redirect console COM1 to be the console input....

ECHO ATDT0742286318 >COM1
PING LOCALHOST >NUL (for a delay otherwise i got another chrs before "busy" in file.txt)
COPY COM1 e:\temp\file.txt

As i know modem is default set on X4 Result codes, Busy and dial tone detect enabled (factory setting) so it automatically sends X4 Result codes to Com1, no need to ask them myself. This is what i think it is happening here.

I can write a batch file that would stop and listen to com1 but that's the problem here, it blocks here, i can't pass to the next line. This is the line in cause:
COPY COM1 e:\temp\file.txt

PS:
Now i would like that the string read from the port to assign to a variable, not a file, maybe will work with the new w2k command set.