Need Wiring Diagram For 151AL Candlestick, 5 Conductor Mounting Cord & 302 Base

[unbeldi]

The five-wire method still does not use ALL of the functionality of the 425 network.  It does not provide a filter for the pulse dialing contacts to avoid contact arcing and wear and radio interference.  To include this requires a six-conductor cord. It is interesting that some of the BSP actually prescribe a six-conductor cord in the diagrams but only use five conductors.

Of course, the dial filter can also simply be implemented by installing a No. 61 filter directly onto the dial, and I would suggest that this is actually preferable, because it eliminates the mounting cord as a potential antenna to radiate the high frequency.  Interference filters should always be installed as close as possible to the source of interference.

It is interesting to note that the late BSPs still list the 61 filter as optional equipment, despite that the 425 has a filter contained, and I suspect the reason is that, which I stated.

Here is what the six-wire solution looks like in a similar diagram:

[poplar1]

The advantage of the method I suggested to Gary, using a 4-conductor cord with a 685A, is that you don't have to modify the telephone: the 202 or 151AL is wired the same for either a 634A/684A or a 685A. That also means not having to purchase a 5-conductor cord to replace the existing cord, and a junk 500 (with the same network as a 685A) may be easier to locate  if you don't have a 302 base or a 634- or 684-type subset available. 

To be honest, I haven't actually tried using a 4-conductor cord with a 685A. I've always used a 684- or 634-type  subset, or 302 base, when using a 4-conductor cord, or a 5- or 6-conductor cord with a 685A. So I'll leave it to others to comment on the audible or functional differences.

[Jack Aman]

Amazingly good and thorough information as always.  Thanks gentlemen.

[unbeldi]

Last not least, it is noteworthy that even a three-conductor sidetone instrument, such as a candlestick, an A1, B1, or any 102-type sidetone telephone can be hooked up just as well, by simply only using the red, green, and yellow conductors, without any modification to the instrument.

One of my workbench devices is a 500-set base with the 425 network, hookswitch assembly completely cut out, and a 6P6C modular jack box installed under the dial.  This can accept either 3-, 4-, or 5-wire adapter cords to test any sidetone or anti-sidetone WECo telephone.  Keeping the dial on the set is convenient, because it permits call origination during testing even with a manual telephone instrument.

[poplar1]

The five-wire method still does not use ALL of the functionality of the 425 network.  It does not provide a filter for the pulse dialing contacts to avoid contact arcing and wear and radio interference.  To include this requires a six-conductor cord.

There is an alternate way of using 5 conductors for wiring a 211L, and by extension a 202, in order to include the F-RR dial filter. It is shown in Section 502-320-400, Issue 1 or Issue 2 (TCI library). Since the 211L is factory furnished with G3- or G1-type handset, off-hook this arrangement is equivalent to a 500 set. However, the line is permanently connected to F and C even when the phone is on-hook.