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From: cybrspc!roy@cs.umn.edu (Roy M. Silvernail)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Reading modem registers in C.
Keywords: registers, 0x3f8, ats#?
Message-ID: <oauyN3w162w@cybrspc>
Date: 15 Aug 90 22:14:23 GMT
References: <10133@hubcap.clemson.edu>
Organization: Villa CyberSpace, Minneapolis, MN
Lines: 24

rmorris@hubcap.clemson.edu (Robert Morris) writes:

> I'm trying to read the registers in a Hayes 2400 modem.  I issue a 
> ATS#? (# - number of the register).  I then check 0x3f8 for the value.
> What I get is an unlikely result (ie. 13 - number of rings that occurred 
> and no one called).  I figure the 13 is the carriage return sent to the modem
> I'm using Turbo C 2.01 and would appreciate any help recieved.

I figure you're right. Your modem is most likely sending an ASCII string
representing the status of the register, and 0x3f8 will only contain the
latest character received from the modem.

If you're using a Fossil driver, the problem is easily solved by reading
characters waiting in the input buffer (using INT 14h). If not, you'll
have to incorporate some kind of input buffering (in effect, a
mini-comm program), and read the waiting characters from the buffer.

Hope this helps.

--
    Roy M. Silvernail   | #include <stdio.h>                 | Does virtual
    now available at:   | main(){                            | reality need
 cybrspc!roy@cs.umn.edu |  float x=1;                        | swap space?
(cyberspace... be here!)|  printf("Just my $%.2f.\n",x/50);} | -- me