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-   -   Interconnecting old telephones? (https://www.vintage-radio.net/forum/showthread.php?t=139739)

baceplate 11th Sep 2017 2:05 pm

Interconnecting old telephones?
 
hi there just joined the forum last week, I collect old GPO phones 200 and 300 series all in working order. My problem is how do I get them to work so as I can call one to another I have 3 phones upstairs one in the living room and one in a log cabin down the bottom of the garden have tried every thing to solve this, I bought a Panasonic 206 which I was advised was all I would need, I could not get it to ring the old phones but it would ring two cheap Chinese phones I plugged in to it, not what I wanted. spoke to a ex BT engineer he advised me to buy a BT micro did not work with the old phones worked with the cheap phones have tried every thing after a day I gave up. As you can imagine I'm down a few quid have tools I will probably never use again seem to have miles of twisted pair cable and no further ahead. reading the post on this forum some of the members seem to have systems I can only dream about, A bit of advice would be very much apppreciated hope to hear from you soon.Bill

paulsherwin 11th Sep 2017 2:15 pm

Re: old telephones
 
Old GPO phones use a separate wire for ringing, so won't ring on a 2 wire circuit. You may be able to generate the ring signal by using the phone through an ADSL microfilter, as these have their own ring capacitor.

A lot of modern hardware doesn't support pulse dialling.

ThePillenwerfer 11th Sep 2017 2:53 pm

Re: Interconnecting old telephones?
 
A bit more information would help.

You say the old 'phones won't ring but does that mean that the bells don't make a noise and that they otherwise work? In other words can they call each other but you simply don't know about it?

How are the telephones wired: the old way — using two wires and their internal capacitors or the modern way with three wires.

Do you get a dial tone? Does it go when you dial?

If it is just the bells it's certainly do-able as the Panasonic 206 works with either pulse or tone dialling. Hopefully somebody who knows about their intricacies will be along later with advise on how to set it up.

Dave Moll 11th Sep 2017 3:32 pm

Re: Interconnecting old telephones?
 
As others have said, more information is needed to be certain, but it sounds as though your old telephone have been converted to use an external ringer capacitor, but you are making two-wire connections from your Panasonic 206 (albeit not a PABX with which I am familiar).

If this is the case and your telephones are terminated with a standard BT plug, what you need is to have the extension lines from the 206 going to master sockets (which contain ringing capacitors), not extension sockets. Alternatively, as Paul says, plugging a BT-style ADSL filter into each extension socket should have the same effect.

The reason that your "cheap Chinese 'phones" will work in this situation is that they will have their own ringing capacitor.

Oldcodger 11th Sep 2017 3:33 pm

Re: Interconnecting old telephones?
 
Only suggestion on extension calling with out a system is extra wires and a buzzer system.
PW- is that an ask for help on the 206. I'd love to help, as I've got a stack of Panasonic manuals ( with some annotated with factory courses ) ,somewhere ( suspect in loft,but with hip problem I can't get to them). But the KXT break down into two sets. The 308 / 616 and the 206/624. The first two require the programming switch on the inside of the case set to program, whereas the later ones use the extension DISPLAY ( 206, can be done with with an non display-if YOU KNOW WHAT YOU ARE DOING. ME- I always carried a display phone ), phone . TWO beeps means code accepted. One means code rejected.
On display ,set phone programming switch ( rear of phone, next to line cord to program). Enter password- default 1234.
This gets you into programming mode. Then follow the guide in the user manual .

Something worth looking out for for folks with old pulse dialling phones are the older A series, but these do need SLT cards to accept non 4W phones, and the older system phones are polarity sensitive on terminals 3 & 4.

Graham G3ZVT 11th Sep 2017 3:45 pm

Re: Interconnecting old telephones?
 
Quote:

Originally Posted by baceplate (Post 974891)
hi there just joined the forum last week, I collect old GPO phones 200 and 300 series all in working order. My problem is how do I get them to work so as I can call one to another I have 3 phones upstairs one in the living room and one in a log cabin down the bottom of the garden have tried every thing to solve this, I bought a Panasonic 206 which I was advised was all I would need, I could not get it to ring the old phones but it would ring two cheap Chinese phones I plugged in to it, not what I wanted. spoke to a ex BT engineer he advised me to buy a BT micro did not work with the old phones worked with the cheap phones have tried every thing after a day I gave up. As you can imagine I'm down a few quid have tools I will probably never use again seem to have miles of twisted pair cable and no further ahead. reading the post on this forum some of the members seem to have systems I can only dream about, A bit of advice would be very much apppreciated hope to hear from you soon.Bill


Hi Bill, can you explain what you mean by a "BT micro"?

You also say that they are in working order, can I assume then that they are already "converted" to use the modern plug and socket and that they ring on incoming calls when connected directly to a regular phone line?


If so, then my next question is what kind of sockets are you using on the end of the cables going to the Panasonic PABX? They need to be primary sockets.
Not necessarily the NTE5 type Master sockets, just cheap PABX primary sockets identifiable by having a capacitor. You will need them for all extensions with a vintage phone attached. as you have discovered, modern phones will ring on a secondary socket without the capacitor.

Here's a good tip if you only have secondaries, find a spare ADSL filter and plug your vintage phone via that.

Graham.
G3ZVT

OscarFoxtrot 11th Sep 2017 6:08 pm

Re: Interconnecting old telephones?
 
A BT Micro is a box including Broadband router, WLAN, & a DECT cordless handset, all in one box. It's been discontinued by BT.
https://www.businessdirect.bt.com/pr...4869-434K.html

If the old phones work on a direct exchange line but not the Pana 206, it needs master sockets or rewire the phones to use internal ringing capacitors. The centre pair of the Panasonic RJ12 connectors connects to 2 and 5 of a British Telecom connector.

If the phones don't work on a direct exchange line, then they need to be rewired internally.

Wiring guides for almost everything is here
http://www.britishtelephones.com/pstconv1.htm

Not sure if the Pana 206 will do it, but the larger systems can have hotline dialling set up so on lifting the handset the system will automatically dial to an 'operator' extension allowing even dial-less phones to be used.

(I had exactly the opposite problem with a Norstar system some years ago, which requires extension sockets with the wires to 3 and 4)

dagskarlsen 11th Sep 2017 6:10 pm

Re: Interconnecting old telephones?
 
I am not sure about that Panasonic, but the KX-T616 or KX-T308 are suitable.

I would not give it up before some simple testing.

The Panasonic uses a RJ11 or RJ12 jack. In the jack the 2 center pins are the interesting ones. This is the line just as the pair coming in to your house if you have an old telephone line.

For most other countries this is enough, but in UK you have had a master socket splitting up to 3 wires via a capacitor. This capacitor are inside the telephone in other countries, and in really old UK phones.

If your older phones has the capacitor, it might be enough to connect a link inside your phone, If it hasn't just ad the capacitor. Most phones will be OK with a 1 microfarad non-polarized capacitor rated to at least 200V

Pictures of the inside and schematics if you have will help us to help you.
If you do not think you get the help you need here, google for classicrotaryphones forum.

dsk

McMurdo 11th Sep 2017 6:50 pm

Re: Interconnecting old telephones?
 
we have the Panasonic SDBS 308 at work and it rings 300 series phones no problem, though the one I've tried has been converted to BT plug with a 3.3k bell resistor. I think Panasonic only recommend a ren of 1 on an 'SLT' equipped extension, though I don't know the 206 intimately. (hybrid pabxs from panasonic require a master socket on SLT extensions and a secondary socket for digital keyphones).

An unconverted 200/300 will have a REN of 4 afaik and may refuse to work or even ring trip the PABX.

Our 308 won't accept pulse dialling on an extension (since it uses TBR and will interpret a '1' as a recall) but will convert MF to pulse for the exchange if so programmed.

Ed_Dinning 11th Sep 2017 9:15 pm

Re: Interconnecting old telephones?
 
Hi Bill, if you want an authentic home exchange there was an article in Wireless World in the 70's detailing construction. It used PO relays and the odd uniselectors, but allowed intercom (dial extensions) as well as dial out.

Ed

radiotechnician 11th Sep 2017 9:37 pm

Re: Interconnecting old telephones?
 
2 Attachment(s)
For old phones with carbon transmitters.

If you want to use the phones as an intercom system, not connected to the Central Exchange, A DC source is required. This source is connected in series with a RET (retardation coil). This system provides transmitter current to each phone. The voice circuit travels via the impedance of the RET.

Then all three phones, and the RET and battery are connected in parallel.

That does not address the signalling issue. Other have suggested a third wire/button/buzzer.

Telco RET units are rather elaborate, and have several windings.
Your RET might be as simple as the coil and core from a 12 volt DC relay, 200 ohms or so.

Each phone will have two wires, Tip and Ring.

The RET system will have one wire of the battery called Tip and one wire of the coil called Ring.
The other ends of the coil and battery are joined together. Join all Tips together, then join all Rings together.

Battery 12 volts or so.

The North American phone system seems to have grown up around four basic coil types:

Induction
Repeating
Retardation
Loading

Attached is end view of a RET coil, and how phone service workers use it.

Biggles 11th Sep 2017 9:41 pm

Re: Interconnecting old telephones?
 
I'm sure that Maplins had a home exchange project and kit going at one time. It was a few years back though. That's if you're really keen. Those automatic dialling extension set ups can cause no end of problems at work if the line has a leak across it. The switch thinks you have lifted the receiver on an extension and dials the control room, but there's no one there. Most annoying for the duty controller.
Alan.

russell_w_b 11th Sep 2017 10:25 pm

Re: Interconnecting old telephones?
 
1 Attachment(s)
Here's a way that may work as an intercom, although I've yet to try it. Couple of PO3000 relays and a 10u capacitor as a transmission bridge. A third wire is necessary and slave LJUs can be used to terminate, allowing 50Hz a.c. signalling operated by the bridging relays.

Tele A is lifted, RLA energises from a 12V battery. RLA2 opens ensuring no a.c. ringing goes back to Tele A, and RLA1 closes putting 50V a.c. onto the bell of Tele B.

Tele B handset is lifted, energising RLB from 12V battery. RLB1 opens and cuts off ringer a.c. supply. RLB2 closes, but the ringing circuit is held open by RLA2. Speech goes round the loop steered by the transmission bridge formed by the relays and the capacitor.

But I suspect baceplate wishes to use a small exchange and 'house' system?

ThePillenwerfer 11th Sep 2017 10:41 pm

Re: Interconnecting old telephones?
 
I remember that Maplin's kit. It was from the late '80s/early '90s as I recall.

Tractorfan 12th Sep 2017 9:53 am

Re: Interconnecting old telephones?
 
Hi,
Years ago I had a few 706 'phones and I connected them together along with a DC supply of around 30 volts or so. I put a choke in series with the supply and when the dial was pulled round to the stop the pulses tinkled the bell at the other end. My young nieces had hours of fun talking to each other along the length of the garden on them.
Alas, I can't remember exactly how I did it.:(
Cheers, Pete.

majoconz 12th Sep 2017 10:55 am

Re: Interconnecting old telephones?
 
If you can hunt out an old booklet called "Out of Thin Air" published by the old Practical Wireless, there is an article in there on connecting two phones together over twisted pair. I needs a 9v battery in each unit and a small bit of Veroboard with a 741 to give the gain. It doesn't ring the bell, the 741 is made into an oscillator to make a loud noise in the other end earpiece.
If you can't find the booklet I'll scan it and send it to you - pm me with your email address.

PsychMan 12th Sep 2017 4:13 pm

Re: Interconnecting old telephones?
 
For 2 phones, the following works very well and I found quite cheap and simple to implement:

http://www.instructables.com/id/Hack...hone-Intercom/

It works on the principle of lifting one hand set to cause the other to ring. The comments on that page should contain all the "UK" settings to get the correct ringing tones out of the VOIP adaptor.

I use the same for an outbuilding, and instead of using 1 VOIP adaptor, I modified the settings so each phone has a voip adaptor, and they call each other over Ethernet, as I have Ethernet to the outbuilding

Graham G3ZVT 12th Sep 2017 4:13 pm

Re: Interconnecting old telephones?
 
What about using an old BT Minimaster 3?
It's a microprocessor controlled PABX, but it has sufficient clicky relays for that authentic vintage feel.

Some time ago I came up with a dialplan for a Linksys PAP-2 ATA that it to be used as a two station intercom as well as making and receiving VoIP calls, however it has no DP support.

A few weeks ago there was a discussion on here about a couple of Grandstream Handytone models, HT502 & HT503, which are very similar devices to the PAP-2 and support LD telephones, so I wonder if my dialplan could be used or adapted for the Grandstream?

Graham G3ZVT 12th Sep 2017 5:30 pm

Re: Interconnecting old telephones?
 
Quote:

Originally Posted by PsychMan (Post 975190)
For 2 phones, the following works very well and I found quite cheap and simple to implement:

http://www.instructables.com/id/Hack...hone-Intercom/

It works on the principle of lifting one hand set to cause the other to ring. The comments on that page should contain all the "UK" settings to get the correct ringing tones out of the VOIP adaptor.

I use the same for an outbuilding, and instead of using 1 VOIP adaptor, I modified the settings so each phone has a voip adaptor, and they call each other over Ethernet, as I have Ethernet to the outbuilding

Hi PsychMan,
Looks like we posted the same thing at 1613!

I hadn't seen that Instructable, but it's a simpler version of what I am doing.
A Hotline would not have been appropriate in my case, as each phone also can make and receive calls on its own VoIP account.
Each extension has to dial 11 to ring the other.

If you are interested, here is my dialplan with line-breaks and annotations after each | separator.
lower-case x are normal wildcard, upper-case X are to anonymize my stuff.


(<01:00441>x.| allow 01
<08:00448>x.| allow 08
<02:00442>x.| allow 02
<03:00443>x.| allow 03
<07:00447>x.| allow 07
<:0044161>[2-9]xxxxxxS0| allow Manchester numbers without dialling 0161
<0161:0044161>[2-9]xxxxxxS0| allow Manchester numbers using 0161
00x.| allow international
<11:XXXXX@sip.discountvoip.co.uk>| INTERCOM
<12:XXXXX@sip.voipfone.net>| SPEEDDIAL
<13:004477294XXXXX>| SPEEDDIAL
<14:00447728XXXXXX>| SPEEDDIAL
<15:0044151601XXXX>| SPEEDDIAL
<16:0044161884XXXX,495>| SPEEDDIAL + 3 digit DTMF
<17:2233435945@rentpbx.mundy.org>| SPEEDDIAL, "Lenny" ammusing anti-telemarketing robot URI
<18:music@iptel.org>) SPEEDDIAL, latter-day "disk of the day" URI

Graham.
G3ZVT

OscarFoxtrot 12th Sep 2017 9:37 pm

Re: Interconnecting old telephones?
 
3 Attachment(s)
Quote:

Originally Posted by majoconz (Post 975139)
If you can hunt out an old booklet called "Out of Thin Air" published by the old Practical Wireless, there is an article in there on connecting two phones together over twisted pair. I needs a 9v battery in each unit and a small bit of Veroboard with a 741 to give the gain. It doesn't ring the bell, the 741 is made into an oscillator to make a loud noise in the other end earpiece.
If you can't find the booklet I'll scan it and send it to you - pm me with your email address.

Page 20 here
http://radio-amador.net/pipermail/cl...hinAir1980.pdf

Also attached in case that URL disappears.

I've been looking for that circuit for 27 years!! :clap::clap::clap: - I thought it was about 1988 it was published. Perhaps it was in an updated version.

Even less technological was the "Stanophone" which comes up on ebay occasionally.
http://www.unipartrailexpress.com/product.aspx?37182

The 10 line telephone exchange with 22 relays is attached if I can find the file. Note the corrigenda on the last page. Also a Cook Abbott ringdown circuit.

As the OP has a working Panasonic system and probably working telephones, however, the simplest thing will be to get them to work together as originally desired.


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