[ale] Weird problem looking at some data capture

Christopher Fowler cfowler at outpostsentinel.com
Tue Nov 20 14:08:37 EST 2007


Solved

The problem was the PBX was sending me 7-bit ascii.  Every 8th bit of
data was high (1) and so I was treating it as 8 bits.  Somehow od knew
this and did the conversion on the fly.  I never told it to convert to
7-bit ASCII.  In my perl program that is gathering data I created a
conversion function

sub toascii {
        my $v = shift;
        my $ascii = undef;

        for(my $x =0; $x < length($v); $x++) {
                my $c = substr($v,$x,1);
                $ascii .= chr(ord($c) & 0x7F);
        }
        return $ascii;
}


This effectively converts the 8-bits into 7-bit ascii. I think ascii2uni
does the same thing but i need to do this in perl myself.  This program
will run for a month just sucking down data. 


On Tue, 2007-11-20 at 10:11 -0500, Asif E. wrote:
> Chris,
>  
> I do see the phone number in that chunk of data, highlighted below.
> Is that what you are looking for?
>  
> Asif
> 
>  
> On 11/20/07, Christopher Fowler <cfowler at outpostsentinel.com> wrote: 
>         I have a device connected serially to a Meridian PBX trying to
>         capture
>         CDR data.
>         
>         >From my END I see nothing but garbage.  The guy I'm working
>         on is 
>         connected to the device via Procomm plus.  He says he can see
>         phone
>         numbers and data just fine.  I can't and I'm in Linux.
>         
>         I did an od -a on the capture and I see the following:
>         
>         0016120   g  sp   d   o   w   n  sp   -
>         -   ]  cr  nl  cr  cr  cr  nl 
>         0016140   N  sp   0   3   8  sp   0   0  sp   A   0   0   1
>         nul   0   0
>         0016160   4  sp   4   2   3   0  sp  sp  sp  sp   1   1   /
>         2   0  sp
>         0016200   0   9   :   4   8   :   4   9  sp   0   0   :   0
>         7   :   3 
>         0016220   4 nul   .
>         0  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp
>         0016240  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp
>         0016260  sp  sp  sp  sp  sp  sp  sp  sp  sp  cr  nl  sp   &
>         3   1   4
>         0016300   7   8   7   1   8   0   0   X   X   X   X   X
>         X  sp  sp  sp
>         0016320  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp  sp
>         
>         I see some numbers that appear to be a phone number in that
>         file.
>         
>         When I look at this file in VI I do not see 3147871800  I als
>         grep this
>         file and come up empty handed there.  What am I doing wrong?
>         
>         
>         
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