NTS (Alcatel) London 8 PABX.

[tuscan24]

New Here, Hello Everyone

Just acquired this 1980's PABX for my new little collection of vintage LD GPO phones.

its configured as 2 x 6 and working pretty well through a bank of 6 Extension Master sockets and connected to my single PSTN. The unit converts LD from the extensions to MF on the PSTN with no problem. Including sending menu selections to online banking etc.

I found a User Guide and Programming Guide on www.britishtelephones.com which was very handy.

My questions:

The backup battery is not holding any programming changes that I make, there are only a few and its no big deal to put them in again via Ext 21. (The eBay seller was very upfront about this) Any advice on where to get one and is it worth the risk of changing.

There is mention that the LONDON series should be able to accept the digit 1 instead of an earth recall, (none of my old phones have a recall button anyway) - I cant get this to work, wondering if it could be a polarity issue or programming option that I haven't found)

I think that if I could find another Extension card, I could replace the unused PSTN card and make it a 1 x7 - Any ideas where to find one?

Thanks for any help

[Dave Moll]

First, the battery backup - I must admit that I've never bothered with this on either my London 8 (also 2+6, which rarely sees the light of day) or it's slightly larger brother, my London 16 (which runs 24/7, supporting twelve extensions around the house and connecting to four exchange lines - BT, CNet x 2 and mobile network adaptor). On the latter, I have a label on the master extension (221) setting out the commands I need to re-input after a power outage.

To obtain a seventh extension card (which I could also do with for my London 8, whose second exchange card is faulty) you would probably need to find a dead London 8 with at least one good extension card.

Your mention of using digit 1 (LD only) is equivalent of timed-break recall, which works on my London 16. TBR shouldn't be polarity-sensitive. I don't think earth recall is supported.

Edit: giving further thought to this, I'm not absolutely sure that a seventh extension would be supported.

[tuscan24]

Thanks Dave,
1. I'll forget about the battery backup and just re-input a few commands if power is lost as you suggest
2. If you ever fire up your 8, perhaps you could confirm 'dial 1 for recall' works on an 8?
3. I hadn't thought of using my spare exchange card for a mobile network adapter. Sounds like a fun thing to do - which GSM to PSTN box do you use?

If I find a scrap 8, I'll let you know

Phil

[AndiiT]

Originally Posted by tuscan24

......There is mention that the LONDON series should be able to accept the digit 1 instead of an earth recall.......

It sounds like your London 8 PBX uses timed break recall and not earth recall, unless it's a programmable option and your PBX is set for the incorrect type of recall.
If your phones don't have a recall button, Timed break recall can be invoked by rapidly "flashing" (tapping) the switch hook once on the phone.

Andrew

[Dave Moll]

As I said earlier, the London series don't support earth recall - or at least my 16 doesn't. Now that I've had time to think about it, I'm pretty sure there isn't even a signal earth provided.

[Dave Moll]

Originally Posted by tuscan24

If you ever fire up your 8, perhaps you could confirm 'dial 1 for recall' works on an 8?

I haven't fired up (or dug out for that matter) my 8, but I have successfully simulated TBR by dialling 1 on the 16. The first 'phone I tried, however, was unsuccessful, so the accuracy of the dial speed may be important.

As has been said, this won't work with an MF (tone) dialling 'phone.

[tuscan24]

Originally Posted by AndiiT

It sounds like your London 8 PBX uses timed break recall and not earth recall, unless it's a programmable option and your PBX is set for the incorrect type of recall.
If your phones don't have a recall button, Timed break recall can be invoked by rapidly "flashing" (tapping) the switch hook once on the phone.

Andrew

As Dave confirms its not got Earth Recall. I have 4 LD phones (706L,312L,232 and 722) and none of them get a recall tone by dialling '1' nor do any get it with hook flash. It could be that none of the dials are set up correctly, but they do all the other dial functions OK.

Oddly, my two mf phones (Converse and Siemens 'brick') both hook flash perfectly. (The extension ports are auto-detect) - As its only a display set up, not a big deal.

[tuscan24]

Originally Posted by Dave Moll

I haven't fired up (or dug out for that matter) my 8, but I have successfully simulated TBR by dialling 1 on the 16. The first 'phone I tried, however, was unsuccessful, so the accuracy of the dial speed may be important.

As has been said, this won't work with an MF (tone) dialling 'phone.

Thanks for trying it out. See my reply to Andrew

Your mention of C*net on your exchange cards has got me interested, I never knew anything about it. I don't want to build my own Asterisk PBX, but use an ATA to the C*net Asterisk host. Would i need an ATA with FXS and FXO to make and receive calls bearing in mind I only have one available PSTN card.??

[Dave Moll]

When you say the MF 'phones hook flash, I assume you mean by briefly pressing the handset cradle switches rather than using recall buttons (configured as TBR).

[tuscan24]

Originally Posted by Dave Moll

When you say the MF 'phones hook flash, I assume you mean by briefly pressing the handset cradle switches rather than using recall buttons (configured as TBR).

Yes, using the cradle.

[hamid_1]

This should be obvious, but I'll mention it anyway. If the backup battery is dead, be sure to remove it in case it leaks and causes damage.

[Pellseinydd]

Originally Posted by tuscan24

Thanks Dave,
1. I'll forget about the battery backup and just re-input a few commands if power is lost as you suggest
2. If you ever fire up your 8, perhaps you could confirm 'dial 1 for recall' works on an 8?
3. I hadn't thought of using my spare exchange card for a mobile network adapter. Sounds like a fun thing to do - which GSM to PSTN box do you use?

If I find a scrap 8, I'll let you know

Phil

'1' wasn't used for recall on the London 8. The London range of PABXs started with the Lonon 12 ( came initially as an LD only system). It was designed by three senior BT engineers who left not long after BT came into existence knowing the 'liberalisation' (the ability to connect your own/rented PABX without BT being involved) was coming. They set about desiging a small PABX with lots of facilities of larger systems. To kkep the price down, the first versions were LD only for both PSTN line and extensions. They knew that OFCOM were not allowing 'Times Break Recall' initially - all BTs systems were Earth Recall only which needed the 3rd earth wire and OFCOM had close links to BT in those days! The 'London' guys designed the London 12 and then the later models L8/L16/L32/L64 to use the older pulse dialling telephones using two wires and no 'Recall Button'. The ability to use older pulse dialling phone not equipped wth an earth 'Recall' button, they craftily used the first break pulse of a dialled digit to act as the 'Timed Break Recall' - the London 8 manual in the User Guide section specifically says only to use the Recall button on MF phones and with LD phones to ignore it and just dial the number when transferring a call.

I went on the various London courses at National Telephones at Frimley Business Park, Camberley about 1985 where there pointed the above out.
The London PABXs were manufactured somewhere on Tyneside. Once Alcatel dropped the London range, some of the former manufacturers employees opened up in Scubthorpe aeea.They could supply most 'London' bits and were a good source well into the early 2000's.

I still have an unusual version of a London 8 which has 'Multi-Network-Routing' from the days before BTs 'Carrier Pre-Seletion'

The 'memory' battery in a London 8 lastsabout ten years. It is a simple job to fit a new button cell.

Ian J

[rambo1152]

We maintained loads of London systems during my time with the ill fated Nationwide Telephone Company based on Bury.
I can't really recall (no pun intended) the trick with extentions TBR that you described, but I do remember some of those systems doing earth leg recall on the trunks as they were earth-start lines.

I never really understood what the advantage was over normal loop-start.
It certainly confused us techs the first time we encountered them!

Did some versions support meter pulses? I cant remember.

[Pellseinydd]

Originally Posted by rambo1152

We maintained loads of London systems during my time with the ill fated Nationwide Telephone Company based on Bury.
I can't really recall (no pun intended) the trick with extentions TBR that you described, but I do remember some of those systems doing earth leg recall on the trunks as they were earth-start lines.

I never really understood what the advantage was over normal loop-start.
It certainly confused us techs the first time we encountered them!

Did some versions support meter pulses? I cant remember.

The first of the London range only supported LD telephones and were designed to use old telephones that the customer might have - most of which probably didn't have an Earth Recall Button. Hence designing the system to use the initial break of the pulse train as 'TBR'

Also as all the BT systems of the day only used Earth Recall, with the introduction of small PABXs with liberalisation in August 1984, it was rulled by OFCOM that only Earth Recall could be used on PABXs connected to the PSTN. (BT convincing OFCOM?) It was annoying as the Plessey ISDX had the facility to provide both ER/TBR but TBR wasn't initially allowed by the PXML which had to be adhered to. Thus ISDXs had to use Earth Recall with MF phones from 1984 onwards initially

As time went by OFCOM relaxed things and TBR was allowed. Hence the reason that the London guys used their crafty idea = not ony saved money on the phones but could use 2 wires to a phone not two pairs!

The London 8/12 upwards could support Meter Pulse Detection by changing the line cards. The London 8 I still have has that facility on the exchange lines.

Prior to Liberalisation, many exchange lines provide for older PABXs were 'Earth Calling' from the days of earlier PABXs. BT loved providing them when you ordered new exchange lines despite being asked for loop calling rather the earth start.

[Eddie99]

"There is mention that the LONDON series should be able to accept the digit 1 instead of an earth recall, (none of my old phones have a recall button anyway) - I can't get this to work, wondering if it could be a polarity issue or programming option that I haven't found)"

- As far as I remember if you set the analogue trunk as a line off an external PBX then that worked - you could also send the recall to line that way to use three way calling and other services from the carrier that required a TBR - so instead of programming the line as PSTN that you program as follows
1751 N D Program Line N off PABX with access digit D - normally 9 but sometimes 0