I'm looking for a device which is able to be plugged into any
basic-rate (BRI) ISDN (aka ISDN2/ISDN2e) line supplied by BT (British
Telecommunications) in the UK, and analyse the line.

I need it to have the following features:

- will display how many digits of DDI / MSN (Direct-Dial-In Number,
Multiple Subscriber Number) the telephone exchange is sending to the
customers premises

- will display the CLIP (calling line identity) number being sent from
the customers phone system to the exchange (even if a different CLIP
to the line's standard number has been specified in the 'phone
system's programming)
For example, an ISDN2 line may have it's standard, pilot number set to
xyz123, and it may have a DDI of abc987. abc987 would be seen by the
exchange as a valid CLIP - I need the device to tell me which CLIP my
phone system is actually sending to line, prior to calling the
telephone company to complain about a fault at the exchange.


This is very similar to the type of thing I'm after:
It's often referred to by telephone engineers as 'the Trend', in much
the same way that householders refer to the hoover rather than the
vacuum cleaner...:
http://www.trendtest.co.uk/trendweb/test/uk/ukwebpages.nsf/vlproducts/AuroraPlus

however at Łuk583, it's far too expensive. I'm looking for simply the
features listed above, at a much more reasonable price. Łuk150 would
be about the limit.

Is there an application perhaps that might be able to provide these
features via an ISDN modem card & a PC? I'm not worried about
'cobbling something together', as long as I can access the line data I
need.