Panasonic 308 PBX for rotary dial phones

[Ryan_1993]

Hello everyone,

I know this isn't "technically" vintage but thought I would post anyway.

I've just managed to buy a Panasonic 308 PBX switchboard, complete with a KX-T30810BE master control phone. I am intending to use this system in my room with my vintage phone collection compromising of...

• Grey Trimphone
  Bakelite 232
  Ivory 741 wall phone
  Green 706
  Topaz Yellow 706
  Green 746

I was just wondering what is the easiest way was to setup this system? I know I will need RJ11 adaptors to plug in my phones. Does anyone know where I can buy something like this (http://www.ebay.co.uk/itm/RJ11-Plug-...item58ac875703) but with a much longer cable? perhaps around10 meters? I will buy several of them. I want an RJ11 plug, to plug into the box and then going into a standard BT plug and socket so I can plug in each of the phones.

One thing I have noticed when reading the manual online is a section called "Connection of the PSTN"

1. insert the modular plug of the telephone line cord into the modular jack marked CO
2. Place the three telephone line cords into holders A & B

I only have one telephone line, so would I just fit one into the first telephone jack as this PBX is in a domestic environment and not an office environment. I assume that the other two line ports which can be used, can be left redundant?

Thanks very much I hope someone can help,

Ryan

[McMurdo]

you'll be able to tell it which exchange ports are equipped with lines or not, it will be in the programming & installation manual. The part number you gave is the CCU isnt it?
I'm not sure if an off the shelf RJ11-BT431 adapter will work. For SLT connection you will need pin 2-3 of the rj11 to pin 2,5 on the BT431 since the RJ11 uses the other 2 pins for data for keyphones. Maybe a pc 'modem' lead is more suitable? If you connect a 4-way pin to pin I suspect you will be connecting the data lines into the SLT socket which must be avoided.

[Ryan_1993]

Thanks for the reply.
Hoping this is an easy setup I really didn't want to start messing with terminals blocks and screwing multiple phone sockets around my bedroom I assumed Rj11 extension cords would have been sufficient. From the set-ups on videos on-line it looks pretty easy. The phones just plugged into the connectors. This was in America though and I understand RJ11 is what they use by default.
So what kind of modem lead would I need and how would I connect it to my rotary dial telephones? Since they have a normal BT plug on them.

[Dave Moll]

Originally Posted by McMurdo

I'm not sure if an off the shelf RJ11-BT431 adapter will work.

Most of the off-the-shelf RJ11-BT431 adaptors that I've encountered connect the inner two pins (2/3) of the RJ11 to pins 2/5 of the BT431. I assume this is what's needed.

The problem comes if data signals are present on the outer pins (1/4) of the RJ11, as these may or may not be connected to pins 3/4 of the BT431. This will not usually be a problem if you use an ADSL filter between this socket and your extension 'phone. N.B. The filter is not being used here to filter out the ADSL signal, which shouldn't be present anyway, it's just that most of these filters include a ringing capacitor to provide the ringing current on pin 3 of their BT431 socket.

Alternatively, use a long cable with an RJ11 plug on one end and open-ended at the other, and put a BT-type master socket on the open end.

[dagskarlsen]

Congratulations.
The setup may be OK as is, try.
The adapters are just a capacitor to the ring circuit. About 1 microfarad works well for each line.

Regarding the setup, you may get lots of help here: http://www.classicrotaryphones.com

dsk

[Ryan_1993]

Originally Posted by Dave Moll

Alternatively, use a long cable with an RJ11 plug on one end and open-ended at the other, and put a BT-type master socket on the open end.

Hello,

Thanks for the reply. Apologies I forgot to mention how I have my phone system currently set up it is as follows...

Master socket (living room) no telephone connected

Hallway has secondary socket BT cordless phone (this is what my parents use as the main house phone)

Kitchen has a phone socket again not used.

Up stairs office has one and coming from this is a 20 metre cable going through the wall and into my bedroom then with a standard BT wall socket connected. Here I have my ADSL filter and then broadband router connect along with just two of my rotary phones.

I was intending to connect the PBX in at this point in my bedroom as all I am bothered about is setting up the rotarydial phones so I can ring each of them which are on my shelf In my bedroom. My parents have no interest in it being connected anywhere else in the house, I would like it just for my phone collection.

If we go back to basics and ignore outside telephone line what is the easiest way to link them up? Into the Panasonic unit? So I can dial and call another phone in my collection?

Much appreciated Ryan

[Dave Moll]

My comment quoted above relates purely to connecting your extensions to the PABX. What I have done with a number of my PABXs is to mount a row of double master sockets onto a backboard for the extensions, each wired back to the PABX with a single pair per socket. N.B. I refer here to doubles where each socket is independent - beware of ones that are really a single master with two outlets. In your case, as I understand that the extension outlets are via RJ11 sockets, this would need to be a cable with an RJ11 plug at the PABX end (either ready made, or if you're feeling brave, a plug fitted yourself onto a cable). So, all of this would be within the installation in your room.

One thought does occur to me if you're connecting one of the exchange lines from the PABX to the 'phone socket, is that you will probably need to disable (or "busy out") the other two lines, so that dialling into the exchange only selects the line that's actually connected to the 'phone socket.

[Ryan_1993]

Thanks

I think I understand what you mean. I need to buy several RJ11 cables. Like this? http://www.ebay.co.uk/itm/ADSL-Broad...item4acd1d3b04 Then at one end chop an RJ11 connector off with wire cutters and then wire that end to a BT Master socket where I can then run an extension cord from. Whilst the other end (still with the RJ11 connector attached) to go into the Panasonic unit.

Or does it need to be a dial up modem RJ11 cable is there a difference?

I assumed (wrongly) that it was going to be just like the American version of this system and pretty much be plug and play with the phones, just by connecting one of the RJ11-BT socket adaptors and then all would work, without having to bother wiring a load of plugs up onto a board. All of my vintages phones are on a large ikea shelf, about 7 foot by 7 foot square so seeing wires isn't going to be much of an issue.

[Dave Moll]

Originally Posted by Ryan_1993

wire that end to a BT Master socket where I can then run an extension cord from. Whilst the other end (still with the RJ11 connector attached) to go into the Panasonic unit.

Or does it need to be a dial up modem RJ11 cable is there a difference?

I'm not sure why you need an extension cord from the master socket. Can you not position this socket near enough to the 'phone to plug it straight in?

If you have a cable with an RJ11 on one end and open leads at the other, it doesn't really matter whether it started life as a modem cable or a telephone line cord. You just need to ensure that it's the wires connected to the middle contacts of the RJ11 that are wired to terminals 2 and 5 of the socket.

[dagskarlsen]

I happen to have a 616 (UK version), and guess yours look like this.

If needed, a factory reset will be by removing battery (arrow) and leave un-powered for a minute or so. No need for reset if it works OK!

The incoming lines (3 on upper left) are connected with only the 2 center wires of the RJ11.
Those may be connected to the master socket A and B wire. Polarity does not matter.

Out you should reserve the first socket for your programming phone, this will use all 4 wires.

Regular phones (rotary or touch tone) use only the 2 center wires. If your phone needs separate ringer wire (typical equipped with British plug from 1981 or later) you will need to split up to 3 wires as on the diagram.

1 microFarad may be good for 1 or 2 phones on the same ext. The master socket uses about 2, a single american telephone ringer uses 0.47.

dsk

[Ryan_1993]

Sorry split up three wires? I'm good at restoring old phones, but this is beyond me.

I don't think i'm going to bother it seems far too complicated, just for several telephones. I guess I should have done some more research and not just watched a couple of videos of the American version in action which seemed like a 5 minute job to set up. The telephones simply all just plugged into the RJ11 jacks and then all worked once the unit was programmed in.

I will just sell it on ebay, at least I only spent £30.00 on it, I never usually admit defeat ever, the unit hasn't even arrived yet, but it just seems like more effort than what its worth.

[Ryan_1993]

Originally Posted by Dave Moll

You just need to ensure that it's the wires connected to the middle contacts of the RJ11 that are wired to terminals 2 and 5 of the socket.

Apologies, but How am I able to tell? it seems quite difficult to find that out from ebay sellers.

looking at the photos would this be sufficient? http://www.ebay.co.uk/itm/RJ11-TO-RJ...item2c66bc07da

if not then I guess I give up, I've been looking for hours online, without success of finding cabling.

[AndiiT]

Hi,
It looks like all the advice is getting you in a bit of a pickle, so I'll try my best to simplify things -

Your Panasonic PBX is primarily designed to be used with dedicated "Key system" phones, such as the KX-T30810BE, which you already have, this phone is also used for programming the system for such things as which extension that you want to have access to external lines and which ones ring on incoming calls etc.

Having said that, it is able to operate with standard "two-wire" telephones once it has been programmed and there is no reason why it shouldn't be, particularly for the purpose which you wish to use it for.

Regarding your question about there being ports for three exchange lines but you only wanting to use one, this is where the programming phone comes in to play as there should be an option to provision each exchange line port individually (i.e from one to three lines)

The RJ11 ports are where the biggest confusion arises, they will all be "four wire" ports, the inner two pins being used for voice and the outer two for data, as has already been mentioned - you need to ensure that when you connect your RJ11 cables up that you use the wires connected to the inner two pins of the socket(s) for your telephone collection otherwise you may cause damage to the PBX circuitry.

I would probably tackle your connection issues as follows - obtain some cheap RJ11 to BT type leads from a local £1 shop, these are often only wired with two wires to the inner pins of the RJ11 plug (but check first perhaps by purchasing one and doing some continuity tests with a multimeter). A good clue is that there is often only two outer pins on the BT plug end.

Once you have established which leads are the inner pair you have two choices, you can either cut the BT plug end off and connect the leads direct to some master sockets (LJ2/1A or NTE5A) or connect a master and an extension socket "back to back" with pins 2 and 5 connected together on each socket (i.e pin 2 of the master to pin 2 of the extension socket and the same for pin(s) 5) connecting the RJ11 plug to the PBX, the BT plug end of the same lead in to the extension socket and your phone(s) to the master socket.

I hope this helps as it would be a shame for you to have to sell the PBX on without attempting to get it to work as planned.

Regards

Andrew

[Dave Moll]

If it's not obvious from the layout of the wires as they emerge from end of the cable, it may be possible to see the colours of the wires inside the RJ11 if it's transparent. Failing that, using a multimeter as a continuity tester (may be a bit of a challenge getting the end of the probe to make contact with the pins of the plug), see which pin conducts to which exposed wire end.

The cables you show look ideal. As they only have two wires connected, that should make it easier to determine which ones they are. The cable will probably still have four wires, but two will be cut short each end.

Don't give up. It sounds like you're nearly there. It really isn't as complicated as it seems at present. I've no doubt that, once you've got it sorted, you'll wonder why it seemed so difficult.

edit: AndiiT posted while I was typing.

[Oldcodger]

Hi, I'm a newby poster, but your post interested me, as I used to install these for a living. We used ( on new kit) to use the panasonic provided leads from the 308 to a box connection 201. CO(Americism for Central office =UK exchange) lines used only two of the four wires. I always used to wire up all the leads for the extensions so that any extension could be either key phone or SLT. On reconditioned kits,we'd use 4w telephone cords and cut off the BT plug. But the colour coding on these can be different from that in the 308 installation manual. You will need a display phone for programming. T

[ThePillenwerfer]

Here's what I'd do:-

• Un-convert the 'phones, ie put them back to the two-wire configuration they'd have used prior to the introduction of plugs and sockets.
  
• Connect the red and white line-cord wires to spare terminals (T11 and T12 in a 700).
  
• Connect the blue wire to T8 and the green to T18.
  
• Remove the BT plugs, fit RJ11s and plug them straight into the PABX.

- Joe

[Ryan_1993]

Thanks that sounds perfectly easy, would I be able to buy an rj11 cable with the end already pre-fitted with a connector instead of chopping up my colour coded cables which match the phones to fit an rj11 connector on the end. I don't mind disconnecting that wiring and fitting new.

[ThePillenwerfer]

I've never seen RJ11 to spade leads on sale, but have never had cause to look. You could always solder the wires to your own spades though.

Having altered the wiring in the 'phone you could just use BT to RJ11 adaptors as you'd know the outer two wires, red and white, weren't connected to anything and therefore wouldn't cause trouble.

- Joe

[Ryan_1993]

Thank you Joe that seems perfect, i guess then I will just rewire them all and use one of the RJ11 adaptors.

Couple of final questions do I still need the 205 rectifier and the 3.3k resistor or can these be removed?

Is the rewiring method explained above the same for the Trimphone and what method would be best used for my 232. Thanks so much

[OscarFoxtrot]

This is how to wire panasonic systems to British phones.

I have 2-line master LJUs (LJU 4/1A), I have chopped off the capacitor/resistor on the first socket to which all 4 wires from the PBX enter, and that is used for Keyphones (Proprietary Telephone in Panasonic-speak). I then continue the A and B wires (Tip and Ring in Panasonic-speak) to the second socket for ordinary (SLT Single Line Telephone in Panasonic-speak) and continue with 3 wires to BT 2/3/5 as usual for extension sockets.

If your phones are 2-wire with a ringing capacitor then just connect to A and B which is 2 and 5 on the LJU, or 3 and 4 (inner pair) on the RJ12.

https://www.vintage-radio.net/forum/...pictureid=3066