Restoring early communication technology

I’ve been looking to improve my home telephony. I recently migrated from a single Siemens Gigaset N510 IP Pro DECT base station as my only device to adding the free, on-premises version of 3CX as a local exchange. The “lines” are provided by Andrews and Arnold using their VOIP service. I started off with Gradwell’s service in 2005 but the pricing was discouraging. I’ve found AAISP to be very reliable and at £1.44 per month for a line, very reasonable. On the few occasions I’ve needed support they have been there for me (to advise me what I’m doing wrong).

The driver for putting 3CX in place is two fold. I had a niggle with the Gigaset, which was intermittently loosing the registration overnight. A reboot fixed it, but it was irritating. The second driver was BT advising the railway that they would cease providing the lines to the two exchanges we run. I needed to understand the capabilities of 3CX, since that’s a good contender for the railway’s future phone system.

Heritage railway

Now, a heritage railway needs to extend the heritage to all of its “front of house” settings. In particular, a modern VOIP phone would look very out of place in the booking hall at Oakworth Station, which is set in 1910. Although the first patent for telephones was in 1876, the use of an exchange requires some form of dialing. The phone at Oakworth station is a GPO 150 canndlestick. I decided it would be a fun project to add one to the house system!

POTS to VOIP

The first challenge is that the phone system in the UK is moving from the traditional analogue service (Plain Old Telephone System) to being fully digital, and our house has been using digital for a couple of decades. I needed a way of bridging that gap. In steps the Grandstream HX801, a relatively low cost Analogue Telephone Adapter. The HX801 is supported by 3CX. It’s micro USB powered and takes an IP line in and provides a “foreign exchange subscriber” port for one line. Grandstream provide a range of these ATAs up to 48 lines. I used their phones a long time ago and they worked well. Alongside an RJ11 cable, RJ45 coupler and RJ45 to BT socket, I had a spare Power Over Ethernet splitter that exposes the POE as micro-USB so I was up and runnning to get that working. 3CX configuration was a breeze.

The ATA also supports pulse dialling so configuring it to work with an old BT pulse dial phone was pretty easy. I had poven that my 3CX exchange supported my old analogue pulse dial phone. Progress! Now to the GPO 150 …

Getting the bells to toll

The usual configuration was a Bellset 1. The GPO 150 requires a separate bellset – the bells are typically wall mounted, not part of the phone. A quick surf through ebay led to a Bell 1a arriving a week later. The bell connected into the Grandstream with some cannibalised RJ11 connected cable and was up and running. Next, finding a credible GPO 150. Ebay to the rescue again and shortly after the bell came the phone.

I had, however, been a little naive. A bell 1a is not the same as a bellset 1.

Note
This is a bell only and has no induction coil or other components. Because of this it CANNOT be used as a direct replacement for a Bellset No. 1 or 25.

Therefore it should NOT be used as the only Bellset on any Candlestick or Telephone No. 162. It can, however, be used as a simple extension bell.
GPO – TELEPHONE No. 150 (britishtelephones.com)

Fortunately, Chris and Vikki Elliott at Vintage Telephony provide the missing component – a Bell 1A to Bellset 1 conversion board, the BS1A21.

The final working system

So, the final set of components is:

A network connection to the 3CX PBX
Power over Ethernet splitter with micro-USB power connector
Grandstream HX801 Analogue Telephone Adapter
RJ11 to RJ11 patch lead (to connect the Grandstream ATA to the home network patch panel)
RJ45 to BT socket converter including surge protection, ring capacitor, test resistor
Vintage Telephony Round Section Line Cord to plug into the BT socket
Vintage Telephony BS1A21
GPO Bell 1a
GPO 150 telephone

Putting all the pieces together, I cam across one final issue. 3CX knows about the Grandstream ATA, and creates a configuration file to fully manage the ATA in 3CX. However, it doesn’t provide a way to enable pulse dialling in the user interface. Time to edit the XML template used to drive 3CX. The template is in /var/lib/3cxpbx/Instance1/Data/Http/Templates/fxs
And the changed line section:
   <P20521>1</P20521>

In conclusion

Its been a fun project. As with all ICT, handling legacy debt has proved a significant cost driver. The phone and bell cost around £120, the BS1A21 and cable came to £50 with postage and the Granstream ATA came in at £44. Given you can get a fully-featured VOIP phone for around £25 on eBay and the old tech cost more, requires more tech debt management and for all practical uses is so much better.

But I would do it all over again!