20AL with 4 wire line cord

[zaphod01]

I bought a 20AL with a 4 wire cord. This is my first candlestick so I have a LOT to learn. I've since read that all 20AL's are sidetone but mine has 4 wires indicating anti-sidetone. 

No subset (other than my 302 base) so I haven't connected it yet, I have a Northern Electric 684BX being delivered tomorrow. I'm also bidding on a couple of 634's and 684's.

Now, the questions...

Could this have been converted to an anti-sidetone phone?

Call I tell anything by simply removing the base?

Should I try a standard 4 wire connection to the 684BX?

Any other thoughts/comments?

[poplar1]

Is the black wire connected to anything inside the 20AL?

If it was converted to anti-sidetone, it should have been marked "120AL." Look at the hook switch contact springs: if there are 3 that make when you go off-hook, it is sidetone. If there are 4--2 sets of 2 each--then it is anti-sidetone.

A sidetone set should have a sidetone subset (534A, 295A, 584A, 334A).

An anti-sidetone set can be used with either a sidetone or anti-sidetone subset (634A, 684A, 634BA, 684BA, 495BP, or 302 base.)

There is at least one way to use a sidetone set with 3-conductor cord to an AST subset. A relay can be placed on the subset end, in series with the yellow lead that goes from the subset to the phone. When you go off-hook, this will activate the relay. The contacts closed by the relay would connect BK in the subset (where the black condenser wire is) to L2Y.

Another way is to use a 5-conductor cord with the AST subsets listed above or with a 685A subset or 500 base (425 network).

[zaphod01]

The finish is so nice on this phone that I'm fearful of the disassembly process. I guess I should have bought a 'starter' candlestick first! It's clearly marked 20AL.

Can I do any harm to the phone by trying the AST hook-up first?

[poplar1]

No harm done, but I wonder where the black wire is connected, if at all.

The middle screw on the bottom holds the phone together. It's best to remove all three, though. That way, you can add some slack in the cords.

[HowardPgh]

I had one wired that way.  The black wire was terminated under one of the perch screws!  It was like the body of the phone was supposed to be grounded through the black wire.
Try the phone just using the normal red/green/yellow to a sidetone subset.

[zaphod01]

Unfortunately, the only real subset I have is the 684BX that arrived yesterday. I also have 5302 base I converted to a 684 and 500 base I converted to a 685.

The 684BX works fine with my 202. However, I am a little scared to hook up the 20AL. Can I just connect the red, green and yellow to the 684BX, like my current connection to the 202, and leave the black disconnected?

[poplar1]

Your 202 should have 4 conductors when connected to a 684BX. There should be a connection between BK on the dial in the 202 to BK in the 684BX. The black condenser wire is also on the BK terminal in the subset.

What if you took the 4-conductor cord from the 20AL and used it on the 202? Then at least the 202 would be correct.

One reason it is so difficult to find a sidetone subset for your 20AL is that so many of them were converted to anti-sidetone. If you already have a 634A, watch for an incomplete non-dial 533A wall phone; this is the metal "hotel set" without a dial. (Almost all the non-dial metal wall sets, like the non-dial candlesticks, are still sidetone. If converted, they would be 633A and 120AL--Always add 100 to go from ST to AST.)

By swapping the covers on the 634A subset and the 533A wall phone, you end up with a good 534A subset and some extra parts to complete candlesticks.

If you have one sidetone subset (534A, 584A, 295A, 334A), you can connect multiple phones to that one subset. And you can connect both sidetone phones (20AL, 40AL, 50AL, 51AL, 102) and anti-sidetone sets (151AL, 201, 202, 211) in any combination to that one subset. When used with a sidetone subset, the black wire from the AST phone is insulated and stored. These AST sets will now be used as sidetone ones.

As discussed in another topic, changing a subscriber to anti-sidetone usually meant having multiple subsets, one for each candlestick or 202. And 20ALs, 50ALs, 51ALs  could no longer be used with the newer circuit, because there are not enough contacts in the switch hook. That's why they were modified and changed to 120ALs and 151ALs. B1 and D1 102s were easier to convert to 202s because only a 4-conductor mounting cord was needed to replace the old 3-conductor one.

[Sargeguy]

You may also consider a 295A subset, or a 333 or 334.

[zaphod01]

I'm watching for a ST subset to come up on eBay. There's a 584DE. Would this work? Also watching for a 533A.

I convinced myself the 20AL might have been converted to a 120AL, hence the four wires. I hooked it the 684BX and it seemed to work fine. 

Now I need to find a complete but raggedy WE candlestick to disassemble and really see how these are wired. A 'learner' candlestick...

Thanks guys! You rock!

[poplar1]

584DE is an extension ringer. There is no induction coil; so, it is neither sidetone nor antisidetone.

There is a sidetone subset coded 584A.

This is a photo of a 584DE:

[zaphod01]

Thanks for the picture of the 584DE! There is not a shot of the inside in the listing. I couldn't find much on that model...

[poplar1]

534A pictures

[poplar1]

295A (sidetone):

http://www.ebay.com/itm/380631054414

[poplar1]

The 295A was furnished in oak or walnut. This is a walnut one:

[poplar1]

WE 334A (sidetone). It is mounted with the gongs at the bottom.

http://www.ebay.com/itm/321159516751