Touch Tone Subset

[NorthernElectric]

This is an idea that I have been working on for over a year now and I finally have one made.  Basically, it's a Northern Electric N515H subset with the magneto and 104 coil removed and a 425 series network and touch tone pad added.

The N515H was missing the magneto when I bought it with this idea in mind.  I had originally intended to use a 315H for this project, but I have yet to find a complete biased ringer for it.  The ringer in this subset is a hybrid B1.  The box was originally equipped with a B1N unbiased ringer but it was a simple task to swap in the biased coil assembly from a B1A.

I mounted the 425 network (I forget which exact version) to the back directly below the ringer and was able to use the original wiring harness for some of the connections.  The touch tone keypad is mounted using a combination of the bracket from the 2500 and a pair of brass corner braces.  These are bolted to the bottom of the box using brass machine screws through 2 of the original magneto mounting holes.  There is very little clearance between the back of the pad and the top of the network.  I haven't needed to yet, but if I find that the brass brackets flex too much I have some rubber gasket sheet to put between the pad and network to prevent contact.

To make it easy to open and close when I need to use the touch tone pad, I bolted a magnet to the original latch screw.  The inner part of the latch is reversed to provide clearance and a steel screw in it attracts the magnet.

I have a D1 connected to this subset and typically call using it's rotary dial.  If I encounter a menu that I need to navigate with DTMF tones, I simply flip down the door to expose the keypad.  Works great.  It still needs a few minor finishing touches.  There is a bit of a gap with the door closed so I am going to file down the nut holding the magnet to the door and/or the screw in the inner latch.  I also plan to make a bracket to attach a non-functional crank handle so that it has more of an original appearance.

[TelePlay]

Very nice "modification" to make your D1 totally functional.

[andre_janew]

And it looks like an ordinary wooden subset!  Very clever!

[HarrySmith]

Very Cool! Great idea to repurpose some useless parts. I wonder if some collector 50 years from now is going to open that up and say, "What the F**K is this??"