Output garbage from serial port

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hey Monks

I'm trying to send commands and receive output from a modem through com1.

Unfortunately i have to do this through windows and so activeperl is what i am using.

this is my source code:

                        open(PORT,"+>COM1") || die "Cant 
                        Open";
                        print PORT "at\n";
                        read(PORT,$buf,3);
                        print "$buf\n";
                        close(PORT);
[download]

only problem is i'm getting garbage ourput >> If i read 400 characters instead of 3 my program code (source) is printed out on the screen along with garbage!!

Dont know what i'm doing wrong - please help!

Thanks a lot
G

20040218 Edit by Corion: Added formatting, fixed CODE tags

_{janitored by ybiC: Retitle from "COM1". One word node titles are a bad thing, very bad}

Comment on Output garbage from serial port Download Code

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Re: COM1 by DrHyde (Prior) on Feb 18, 2004 at 13:17 UTC
You should turn off perl's output buffering if you're using `print` - see `$\|` in `perldoc perlvar`. And because you're using Windows, I expect you need to use `binmode`.	[reply] [d/l] [select]
Re: Output garbage from serial port by bageler (Hermit) on Feb 18, 2004 at 19:40 UTC
have you tried using sysread for reading from a system device?	[reply]