Setting up Asterisk in the UK

I am setting up a PBX for a small company here in the UK and am a little unsure how to proceed. I am happy with the asterisk, software and digital phone setup side but its the connection to our phone company that is puzzling me.

The company requires 5 lines for its incoming and outgoing calls. It has one number for customers to call that need to be able to group hunt through the lines so at the very least they can be put on hold or get a message that all lines are busy.

BT have given me a choice for 5 analogue lines terminating in standard BT (British Telecom)sockets or 6 digital lines terminating in a junction box. I am not sure whether either solution is the right one.

In order to set this up to correctly what do I actually need to ask my phone company for in order to have one number that will hunt through 5 available lines for a free line. Do I go analogue with 5 Digium X100P cards (or equivalent)? Do I have some way of connecting BT’s digital lines into the PBX? What about using ISDN and how might that work? Alternatively we have the option of direct VoIP – but the question always arises (and this is the bit of knowledge I am missing) – how do we sort out 5 bi-directional lines with the ability to expand further if necessary.

We are not tied specifically to British Telecom so we have some flexability.

Any ideas you can provide would be most helpful and greatly appreciated.



Hmmm…I’m also considering the same options for a client…although I mess around with SIP providers with analog…I haven’t gotten round to installing my first digium card yet (it only arrived this morning!)

So…all of this in what I’ve learned from nosing around…not from experience…

First off…some Britishisms…as I get the impression you’re not familiar with our dear old Beetie!!

PRI is known here as ISDN30 (between 8 and 29 digital channels of ISDN on one circuit)

BRI is known here has ISDN2e (2 channels of ISDN on one circuit)

The analogue route you’ve been told about is by using multiple analog trunks all on the same number. Effectively, a hunt group - where incoming calls to that number try the first line, then 2nd etc etc

In the states I understand that each separate line has it’s own number, and the telco does the hunting. Not the case here. Each one is a “slave” of the same number.

If you could persuade the client that having 8 “trunks” would be better than 5 - and also persuade them that having DDI numbers (direct lines) would be an advantage - then I’m tempted to go the ISDN30 route with 8 channels activated. BT can transfer/“port” analog numbers across to the ISDN - but can only port I think 6 existing numbers to a circuit. Sometimes, if the old lines come into one end of the exchange, and the new ISDN circuit goes out the other (in a large exchange) they will grumble, moan and say no. If you can port the fax number and get * to detect the faxes, then it means that they have 8 fax lines…or 2 fax and 6 phone…or 3 of each etc etc etc!!! Their fax machine can sit on an extension…and be used for outgoing faxes.

Here’s why I’m tempted to go ISDN30 - hardware costs.

According to (I’m nuffing to do with them…so don’t start!)

Digium Wildcard PRI card TE110P = £299


1 x Digium Wildcard TDM04B card (4 FXO ports) £219.99
1 x Digium Wildcard TDM01B card (1 FXO port) £89.99

So almost exactly the same cost. But think of the flexibilty with ISDN30!

If you went with ISDN2 / BRI - then you’d need multiple BRI cards…and that gets VERY expensive.

Setup is more…£1000 for 8 channels of ISDN30/PRI - and then approx £15 per month per channel

The nice thing is…you can simply get BT to add more channels as it’s required.

The flexibilty of ISDN30 is superb…being able to add unlimited DDI numbers to the ISDN for just a few quid is just brilliant.

One thing to bear in mind. Outgoing Caller ID. AFAIK you have to specify one of your numbers which is used as the outgoing caller ID for ALL of your channels on a particular circuit. Perhaps someone could correct me, but I understand that you have to commit to one number (e.g. main general number) as your outgoing.

HOWEVER…I’m no expert on setting ISDN30 up on an * box…I’ve only used it on hardware PBX’s…so can’t recommend precise hardware.

Good Luck!