Another phone - Cortelco Key system phone...

[twocvbloke]

Seems this month is a phone month for me, Panasonic phone (goodness knows when that'll arrive!), BT payphone (still waiting, delayed by snow), shiny new Samsung GalaxyS III mobile (arriving tomorrow!!), and now this!! A Cortelco Key system phone!!!

http://www.ebay.co.uk/itm/150975416106

Managed to talk the price down by a fiver from £24.99, and the description is ever so slightly wrong (cos it's not a GPO 776!!), and I've seen similar Cortelco models so know it has LED indicators below the buttons rather than illuminated buttons (I think!), but I haven't a clue what the other buttons are for, they look like something generic that you can pick up at an electronics shop, still, we shall soon see, well, next week at the earliest though...

I've been reading other threads on how to get these to work on a standard POTS line(s), and how to power the lights, but, I'll wait until it gets here before I start buying up other parts to make the thing work...

And a reference pic:

[poplar1]

It's for 1A2 Key, so the LEDs should work on 10VAC.
Keys are probably HPPPPP or H P P P/S P/S P/S.
H=Hold P=Pickup S=Signaling (I know, 2 LLs in UK--here the consonant is doubled only when the syllable is accented (accentted???)

[Adam]

The most common uses for the other buttons are:

1. If the phone has "button restoration" (line keys pop up when receiver is placed on the switch hook) then one of the buttons is a "recall" button, allowing you to get a new dial tone without pressing the switch hook, which would pop up the buttons and cut off the line you were on.  This is the only way to do a "flash" on line for call-waiting or something like that on a set that has button restoration.

2. If the set has access to one or more ground-start lines, one of these buttons could be a ground button, which allows you to get a dial tone after selecting the line and lifting the receiver.

3.  A signal button for a manual intercom.  Usually one of line-key buttons is used for this function, but if the phone has 5 active lines or 4 lines and an intercom line, then an addition button is required.

[poplar1]

Adam, do you think these momentary buttons were factory installed or installed in the field?

[Adam]

It is hard to say without seeing how the buttons are physically wired internally, but the style of those buttons (red and black, round, slightly protruding faces with a silver flange) are consistent with buttons that ITT did factory install for options on its sets from that time period.

Western Electric would never have used "off-the-shelf" parts in their phones like that, but ITT and Stromberg Carlson did in the later years.

[twocvbloke]

The one thing I hate about ebay is the waiting for things to arrive after buying them, I hope this set arrives soon...

Definitely could do with something else to play with that is a challenge, seeing as I have no amphenol cables I can butcher*, at least not yet, and a for a 10VAC PSU, well, that'll be fun to find, I have a 10VDC PSU or two (cable modem PSUs, spares left over from cable broadband), but, if they need AC rather than DC, that could be an issue to try and work out somehow...




(*the Nortel system has one, but it's the link cable between the KSU and the breakout box, though that said, maybe I could use the latter to connect the phone up somehow without cutting the cable up, that's got me thinking now!!)

[Owain]

Presumably you require a female to open end?

Or SCSI-1 used the same 50-pin amphenol connector, and terminators and gender changes for that are readily available.

[twocvbloke]

Presumably you require a female

That wouldn't go amiss in my life.....

Anyway, I have had a look at amphenol cables like that, some of them are just a bit pricey, but I have looked at ones on auction which are much cheaper, so will go down that route methinks...

When the phone comes in of course...

[twocvbloke]

I've got it at last!!!

Not sure how the heck this thing works, it's a right rat's nest of wires in there, wouldn't know where to begin thinking about making it work on a standard line (or lines)....

And those two additional buttons, well, the Black one by the hook goes from G to the back of the keypad (terminals not marked), and the Red one goes from G to 5 on the terminal board...

Haven't a clue what they do still, but now you lot know and will probably have an answer, or a better guess than mine, which is none...

[Adam]

The G terminal on the network could be used for anything, so it's no clue as to the operation of the buttons.

My educated guess is that the black one, which is connected to the back of the touch tone pad, and therefore is line-related (not something like an intercom signal key), is probably a recall (flash) button.

Since the red one also goes to the G terminal, that means it could be line related too, and could possibly be a ground-start button.

[twocvbloke]

I was rummaging through the box (original, if a bit battered) looking for the windows for the number cards, and found a circuit diagram for this phone, and yep, black button is Recall and the Red button is labelled as "GND. SW.", so, it's a ground switch of somesort...

I noticed on the box that it was made in September 1989 though, and ITT-Alcatel-Cortelco's unique numbering system seems to call it an 880850-044, though the circuit diagram says that it's either 2564 or 2566, but given that only the 2566 can have the recall button, it must be a 2566...

And one thing I'm pleased about, the handset, it's not the same quality as my Cortelco 2554, it's much better, I guess this was before the days of making their stuff as cheap as possible...

[twocvbloke]

My ponderings on the BT-nortel "Box Connection 20A", or connection box in non-GPO english, were valid, cos I located the Line 1 pair on the krone terminals (K9-1), and connected up my BT linesman phone, and hey presto, a connection was made, no ringer but that's cos the phone isn't wired up for that, yet...

And these amphenol cables are tough things to manoeuvre into position and hold them there, good thing the nortel stuff has velcro straps to hold the plugs in place...

[twocvbloke]

Well, maybe not such a good idea to use the Nortel box, it ain't fully wired up to the amphenol socket, so some pairs are missed that the phone needs (like Pair 20 & 45, the ringer, that's not connected)...

Ah well, I guess I shall be buying an amp. cable after all...

Still, the ringer works, after holding two wires to the right pair to connect it up, risking getting a nice electric shock if I slipped....

[twocvbloke]

And the LEDs light up perfectly on 10vDC, so long as the polarity is correct...

Only annoying part of that is I was looking at a diagram on here for a 565 (recent thread) and trying to work out why only the first LED would light and the other four didn't (no Hold light, so no point trying that!!), turns out they used less wire in this by utilising Pin 28 as the lamp ground (LG on the diagram) rather than having them paired up on the amp. plug, it helps to look at the right diagram...

I think I'll go start up another thread on this phone, so I can stop hogging the auction section...

[poplar1]

IIRC the WE 564 and 2564 sets have all the lamp grounds stapped to the first LG, but they are also strapped together in the amphenol plug (the one on the mounting cord).