While there were still landline connections available it was not uncommon for those who had functional auto or CB phones to connect these to the line. Generally these old phones worked as well as they ever did before DTMF dialling and electronic ringers became all the rage. Of course these were unapproved equipment and if they had external metal fittings such as a dial or metal base then they no longer met the safety standards. However given that they did not have external power supplies, there was not any great risk of high voltages getting onto the line in normal use. The only practical limitation was that it was not possible to dial # or * without a pulse/DTMF convertor such as a Dialgizmo.

With the looming Australia wide change over to the NBN whenever that might be (certainly not before 2025 where I am in the far, remote, outback hamlet of Canberra) there was discussion on another thread about how an old phone might be able to be connected to on of the two telephone ports on the fibre modem that was to be installed at each sub's premises (assuming the original FTTP plan). The moderator Brad did, given his professional background, quite rightly raise the matter of electrical safety to which I made the point that in terms of isolation from the exchange a non-conductive glass fibre was hard to beat. Please refer to the original thread for the messy details.

Just recently I was made aware of the existence of two different items of gear that allow old phones to be 'connected' to the mobile phone network. This method has the safety advantage of a rather large air gap between the 'naughty' old phone and the switching equipment. Both of these units accept decadic/loop-disconnect/pulse dialling and are also capable of ringing an electromechanical bell. I have now been able to buy one each of these units and to test them. Both units worked with most of my old phones so I thought that the information might be of interest to others with an old phone that they would like to use. While I am in Australia it appears that at least one of the units is readily available in both Britain and the USA so non-Aussie readers are not excluded.

The first unit was a Simado GFX11 Gateway Dialler which is designed to connect a PABX to a mobile (US = cellular) network. However it works just as well with a single phone plugged into an RJ11 socket on the back. It runs from an external 12V plugpack and needs a standard SIM card to be 'seen' by the network as a normal mobile phone. Simply insert an activated SIM card, plug in your phone, turn on the power, wait 30 seconds for the SIM ID number to register on the network then dial a number as you would from a landline phone. My unit worked with either an AldiMobile/Telstra or an Amaysim/Optus card so you have your choice of carrier. If the phone number associated with the SIM is called then the bell in old phone rings with the usual cadence. (Note that you cannot receive/send SMS messages or easily retrieve Voicemail messages if you need to dial a # or a *.)

I used a number of different old phones in my tests including a PMG 801AT, a BPO Tele 706, a PMG 332AT and a WE 500. All of the phones tested except the WE 500 rang properly despite the ring voltage being only 50V at 25Hz. The WE 500 has a smaller capacitor in the bell circuit, a bias spring to prevent tinkling and is designed for 90V at 20Hz so one or more of these factors may have been the issue. Dialling out was sensitive to the speed of the dial and if a dial ran slow (i.e. less than 10pps) then the first pulse in the series would be missed (so dialling a 6 was counted as a 5). Oddly the WE 500 with a dial that seemed to be running too fast, was the most reliable when calling. This suggests that it may be something to do with the duration of the first break that is necessary for the pulse to be counted. Speech transmission and reception was dependent on the quality of the carbon microphone and receiver in the old phone and there was some of the usual 'mobile phone' noise just audible in the background.

I bought my GFX11 secondhand on eBay for $65 but they are available directly from several phone equipment dealers. Note that the GFX11 is 2G unit so it can only be used with Telstra until April 2016 and Optus until December 2017. There is a GFX11-3G unit available for about $500 new and this as the name implies, should work on 3G with either carrier. So far I have not been able to test this unit but I assume that it will operate the same way with old phones.

The other unit is an XLink BT Cellular Bluetooth Gateway which I bought on-line new for $75. It is designed to connect up to three Bluetooth enabled mobile phones to a single analogue phone plugged into an RJ11 socket. It runs from an external 12V plugpack and is 'paired' via Bluetooth to a mobile phone the same way as the 'hands free' arrangement in a car. (Note the two air gaps for extra isolation means it is twice as safe!) The mobile phone is the interface to the network which can be 2G, 3G or 4G depending on the frequency band used by the mobile phone. If the mobile is within about 30m of the XLink unit then calls can be made from or answered on the attached phone. Otherwise the mobile phone can be taken away and used as normal while the analogue phone stays put at home (and probably sulks). Once the mobile phone is back within range of the XLink unit then the analogue phone is active again without any additional fiddling.

I have my XLink unit paired with a Telstra 4GX Buzz on the Telstra 4G network and an old iPhone 3 on the Optus 3G network. Again I used the same lot of old phones to test dialling out and calling in. When dialling out all phones worked correctly regardless of the dial speed. The dial tone was not the standard frequency but I did not consider this to be an issue. The mobile phone hosting the call was the first one paired, in my case the 4GX Buzz, but if this is absent or switched off then the next paired phone hosts the call. Calling any of the paired mobile phones makes that phone ring with whatever ring tone is set and also rings the attached analogue phone with (sadly) the US ring cadence. All of the phones tested except the WE 500, rang properly. Again transmission and reception was dependent on the quality of the carbon microphone and receiver in the old phone (but an 801AT via the iPhone it was better than the iPhone itself).

So we now have two possible ways to (safely) connect a phone from the 1920s or 1930s to the 21st Century phone network. I understand that there is now an (affordable?) add-on 'sleeve' that converts an iPhone into a satellite phone so the sky is the limit!

Thanks for that very useful review.

Note that the GFX11 is 2G unit so it can only be used with Telstra until April 2016

Telstra's 2G network will disappear on 1 December 2016. I know, Telstra keeps reminding me!

You are welcome GTC.

On the basis of doing away with the landline, I have purchased a GFX11-3G which arrived today. I tested it with the same old phones (except the WE 500) and all dialed out correctly and rang properly. The dial tone is the usual pitch and the ring cadence is correct British/Australian version. The unit is pricy but works well. I plan to try linking it to a 2+5 Cordless switchboard so I can demonstrate (= play with) a selection of my collection.

The date I gave for the closing of the Telstra 2G network was what I was told for Canberra. I think that the 2G network is being progressively closed down as I know that in all of the towns in country NSW where I travel regularly my old Nokia phone will not work anymore. Perhaps December is the month when the last cell will be turned off.