ISDN

[Lectrician]

I have fitted several PBX's to analogue lines, and if interested in ISDN.

I have a few questions.

How many numbers come as standard with an ISDN line?

If you had 3 2ch ISDN lines, would that give 3 numbers?

Can DDI numbers be programmed to individual extensions and to departments?

If converting from an analouge system to ISDN, how can all the numbers be brought over? ie. 3 huntgroups on analouge.

What is MSN, and how is this different to DDI?

Is ISDN30 always brought in on fibre?

Any info or links would be great

[amateurandy]

Hello Lectrician, most of the answers to your questions will likely depend on the PABX you connect to the lines, that sorts out the numbers. For an incoming call on a digital line (ISDN) the PABX gets lots of information it can use to route the call correctly including (usually) the number called and number called from.

Assuming BT are supplying the lines there's very little relationship between digital lines and the number ranges. If you want more numbers, and they're available, you can buy them. e.g. A few years ago, organising an office move, I bought a 2000 number range from BT. I think it was initially served by just one ISDN-30 trunk, or maybe we had 2 trunks, one for incoming only and the other split between incoming & outgoing. The PABX was a upper-range Nortel Meridian - a biggish beast the size of several US-style fridges.

I've only ever seen fibre for ISDN30 and I think BT now use it for almost anything new.

Numbers in general are totally portable.

DDI can do almost anything you want, provided the PABX programming allows it.

I'm not a BT/phone expert (just an IT guy who's had to deal with phones a lot) so hopefully someone else can expand on that.

Andrew

[Smart Electrics]

Hello Lectrician, most of the answers to your questions will likely depend on the PABX you connect to the lines, that sorts out the numbers. For an incoming call on a digital line (ISDN) the PABX gets lots of information it can use to route the call correctly including (usually) the number called and number called from.

Assuming BT are supplying the lines there's very little relationship between digital lines and the number ranges. If you want more numbers, and they're available, you can buy them. e.g. A few years ago, organising an office move, I bought a 2000 number range from BT. I think it was initially served by just one ISDN-30 trunk, or maybe we had 2 trunks, one for incoming only and the other split between incoming & outgoing. The PABX was a upper-range Nortel Meridian - a biggish beast the size of several US-style fridges.

I've only ever seen fibre for ISDN30 and I think BT now use it for almost anything new.

Numbers in general are totally portable.

DDI can do almost anything you want, provided the PABX programming allows it.

I'm not a BT/phone expert (just an IT guy who's had to deal with phones a lot) so hopefully someone else can expand on that.

Andrew

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ISDN30 comes in Fibre and copper (Copper is 3 wire provide)

ISDN2e has 1 number for both channels but can have more with MSN subscription realey its like having extensions numbers on the main number

If you require further information log onto BTs web site www.bt.com

or any other telcos site that can provide ISDN

How many numbers come as standard with an ISDN line?

If you had 3 2ch ISDN lines, would that give 3 numbers? YES

Can DDI numbers be programmed to individual extensions and to departments? As far as I am awaire

If converting from an analouge system to ISDN, how can all the numbers be brought over? ie. 3 huntgroups on analouge. AS LONG AS THE NUMBERS ARE COMPATIBLE WITH ISDN SHOULD BE NO PROBLEM

What is MSN, and how is this different to DDI? MSN STANDS FOR MULLTI SUPSCRIPTION NUMBERING

Is ISDN30 always brought in on fibre? NO

[Simon_B]

I should be able to help you with all this as work with it all week !:

How many numbers come as standard with an ISDN line?

[A] 1 as standard with ISDN2 ad ISDN30

If you had 3 2ch ISDN lines, would that give 3 numbers?

[A] If you ordered 3 seperate lines, then yes - but for a PBX it would notmally be 3 lines (6ch) on the same number, bit like the old auxillary working analogue lines.

Can DDI numbers be programmed to individual extensions and to departments?

[A] Yes most ISDN PBX's can do this if they are worth their salt.

If converting from an analouge system to ISDN, how can all the numbers be brought over? ie. 3 huntgroups on analouge.

[A] In most cases, BT will charge for the conversion and bring the numbers over to the ISDN lines.

What is MSN, and how is this different to DDI?

[A] MSNs is supplied on ISDN PMP, DDI is supplied on ISDN PTP - PMP (Point-to-multipoint) is where to you need to plug lots of devices into the ISDN line (i.e. PCs, PBX, Video-Conference etc), each terminal is programmed with its number so it recognises and answers when its MSN receives a call.

PTP (point-to-point) is normally used for a PBX, with DDIs - all DDIs hit the PBX and are programmed to route to the various extensions and departments.

Normally DDIs etc are ordered in blocks of 10. MSN is Multi Subscriber Numbering.

Is ISDN30 always brought in on fibre?

[A] Nope, regularly brought in on Copper, especially for the smaller business who are ordering perhaps 8 channels of ISDN30.

Any info or links would be great.

The obvious one is: http://www.bt.com/isdn

This is a very useful one: http://www.mckerracher.org/isdn/index.html

Regards

Simon

[Smart Electrics]

Better explained Thanks Simon That will teach me to rush

[Lectrician]

Thanks guys, it is very clever technology.

I have fitted several analouge systems, but am considering quoting for an ISDN system for a local pub (acually two pubs next to each other, with a large office aswell where the staff run the whole chain of pubs).

They require 4 seperate hunt groups, and i was considering ISDN, as it can be used with DDI for the fax machines to save on lines, and also, the PDQ's (x6) then do not need to occupy 6 seperate lines (seems a waste).

Just need one analouge line then for the broadband. (and that seems a waste, as thats a wasted speech line!)

[Smart Electrics]

Not necessarily the single speech for ADSL could be used as a POWER or ISDN fail line but other then that good choice

[amateurandy]

the single speech for ADSL could be used as a POWER or ISDN fail line

Or for the alarm?

I've worked on quite a few computer/comms rooms designs and we ALWAYS had at least a couple of good old copper POTS lines for emergencies.

[Smart Electrics]

Or for the alarm?

I've worked on quite a few computer/comms rooms designs and we ALWAYS had at least a couple of good old copper POTS lines for emergencies.

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[Guest]

the PDQ's (x6) then do not need to occupy 6 seperate lines (seems a waste).

Just need one analouge line then for the broadband. (and that seems a waste, as thats a wasted speech line!)

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re the PDQ's, you'll have trouble with them on a PBX. Some of them can be set to dial a 9 on the outgoing calls but during the night the credit card co. dial into them to download the takings. I didn't realise this until recently when I put a PDQ on a PBX and the customer didn't get any credits for a week! All the PDQs I've ever fitted have gone on an analogue line so the CC co. can dial in as they haven't got the hang of PBXs yet!

What I have found, and this varies from machine to machine, is that the PDQ sets itself to answer all incoming calls at a certain time so the CC co. dial and it automatically connects to the remote computer. I've managed to fit one PDQ on a PBX recently, by setting automatic night service to direct the CO line that the CC co. dial in on directly to the PDQ extension for a couple of hours around the dial in time. Depending on how they want the system setting up depends if this is a viable option or not. I'm also not sure if the PDQs can share a line or not, although I've never tried it.

Re the analogue line, always useful as an emergency power fail line or for signalling of various alarm equipment. Sometimes I'll use them as a fax, although I generally use DDI's so have the fax in the same range as the main no's.