[Novalug] Speaking of house cleaning....

Roy Wilson emperor_wilson@verizon.net
Fri Aug 26 15:29:29 EDT 2011






> On 08/24/2011 01:38 AM, Roy Wilson wrote:
>>  I need a sniffer for a 2400bps modem line.  I've got a proprietary
>>  old PC system that connects to a dial-back system so that system can
>>  talk to yet a third system (embedded computer) with the PC as the bridge.
> 
> How to make a serial tap:
> http://www.chipkin.com/articles/rs232-serial-port-sniffing-snooping
> 
> Where to get a copy of Linux Serial Sniffer:
> http://www.kclug.org/pipermail/kclug/2000-January/000530.html

  If I *could* sniff at a serial port, I'd just drop in a wye branch and plug it into a laptop.

  I need to sniff the phone line, and can't interrupt the data stream.

  I'm going from an embedded system sending encrypted data to a PC I can't get at the guts of that has a motherboard 2400bps modem to talk to a dialback system.

  The far end dialback just sends reqs, the embedded system transmits back patterns of register levels.  I need (alright, WANT:)) to know what those registers are sitting at.

  The only way I can see to do it is to sniff the phone line itself.  I have a banjo I can drop in-line, but short of recording a session I don't see how I can sniff the data itself offhand.  I *used* to do it for 300-1200bps lines fairly frequently, but I wasn't using a PC back then.



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