HI Mark,
You have an older ISDN30 circuit - I think these were DAS based but I'm not entirely sure. We've never connected a digium PRI card to one of these (as far as I know). We have, on the other hand done a lot of the newer ISDN30E installs. ISDN30E (which is all you can buy new from BT now) ONLY delivers over regular cat5E (no twin co-ax). The wall-box is smaller and the diagnostic lamps are located at the side of the unit.
WE have a lot of customers running with ISDN30E circuits and they work beautifully with SARK/Sail/Asterisk. SARK/Sail will auto recognise the cards and set them up automatically for the E1 circuit.
Looking at the photos of the connectors on your wallbox, I think you need to speak to BT about the cat5 outputs on that circuit and what they do . If the cat5 output delivers regular E1 ETSI then you should be OK. If not, then I think you may need a new wallbox.
Also, if you have more than 8 channels activated on your PRI then we would suggest you use the TE207P/TE212P card rather than the TE120P. The TE120P has no echo cancellation and Digium only licence HPEC (the high performance echo canceller) for up to 8 channels. This could leave you with a problem if you do get echo on your circuit.
As you may or may not know, Selintra is the only Digium-registered Asterisk reseller in the UK. All the cards and bits you might need are available straight off our website. You can also call us anytime with any questions you may have and we'll do our best to help.
www.selintra.comKind Regards
S