PBX advice please

[Justin <justin@xxxxxxx>]

I know it's not strictly HA, but it's nearer the mark than apple storage
;-) ...

The company I work for is looking at replacing its ageing telephone system
(BT
Ambassador) and having had some seen some of the quotes, I thought I might
have
a bash at it myself, but would appreciate some advice...

The current system has 2 lines on one number. The new system would need to
also
accommodate a 3rd line which we already have.

At the moment there are 2 largish BT boxes, a "Network Test and
Termination
Point" and a "Distribution Frame".
Do both have to go, or just the distribution frame?
Would BT have to de-commission it/them?

The Panasonic KXTA624 looks like a good system and can be had for £374 from
TCL.
Anyone have any better suggestions?
This system has an RS232 port, so is it possible to program it using a PC?
The
docs I've seen mention connecting to a PC, but don't say what for.

I want to re-wire all the phone points.
Any reason not to use CAT5 for the cabling?

Any other advice?

Thanks,
Justin.