From: Phiber Optik <phiber@eff.org>
Date: Sat, 6 Feb 93 22:49:38 PST
To: gnu@toad.com
Subject: Re: 'Sunday Times' article on GSM changes
In-Reply-To: <9302061733.AA10282@toad.com>
Message-ID: <199302070648.AA14155@eff.org>
MIME-Version: 1.0
Content-Type: text/plain


> 
> Thanks for going into more detail on the REMOB fantasy.
> 
> Can you tell the group what facilities are available that actually do
> allow a technician to monitor a particular line (or group of lines),
> e.g. what could a telco emp or a phone phreak do (regarding a short or
> long term wiretap) if they wanted?  And what facilities are *actually
> used* when a court-ordered wiretap is implemented?  My impression is
> that the two are different.
> 
> 	John
> 
I'm glad you brought up this subject, John, because there is indeed a good
deal of misinformation in this area.
I'll start off with some of the numerous facilities available to a telco
technician.  The first I'll mention is MLT (Mechanized Loop or Line Testing),
a system which is part of the LCAMOS group of systems (Loop and Cable Admini-
stration Maintenance Operations System).  Used by Repair Service Attendants,
it's seamlessly accessed through LMOS (Loop Maintenance Operations System),
when the attendant specifies a 'mask' (form type) that would involve a real-
time test to be performed.  At the heart of LMOS is a System 370-type pro-
cessor.  Attendants access the various functions through a Front End (FE)
system, commonly running Unix.  The data comprising customer records and
their corresponding trouble reports/service histories is kept on a high-
capacity storage system (nicknamed the HICAPs).  Each front-end accesses
data from different HICAPs for the respective areas they cover.  Getting
back to masks, when the attendant gets a call on 611, upon the customer
hanging up, they usually issue the TEST mask, which accesses MLT which in
turn establishes a metallic connection to the phone line.  MLT then carries
out impedance, capacitance, frequency/amplitude response tests (at 404Hz,
1004Hz, and 2804Hz, standard), tests for line activity, etc., etc.  The
attendant then has the option to open a trouble record (using the ESTablish
mask), to initiate further testing and repair, possibly dispatching someone,
etc.  I'm getting a bit off topic, but I thought some background was in order
rather than just saying "MLT monitors lines, so there".  What I'm driving at
in this scenario is that there is also a mask known as TV, for Trouble
Verification.  The /FORm associated with this mask requests such information
as the phone number, the 3-digit employee code, a callback number for security,
and the type of TV (RCA, Magnavox, Toshiba, just kidding :), types being talk,
(the attendant can be heard) or monitor without speech path, to name the most
relevant.  It would not be impossible to substitute "someone with a computer
and the know-how" in the place of the word "attendant", but don't overestimate
this possibility.  It's bragged about FAR more than it is actually done.  But
it remains a possibility.
I'll continue this in successive messages, so it's in manageable chunks.