Trimlines -- Hard Wired, Semi-Modular & Adapted Modular

[rp2813]

A looooong time ago I posted about a green rotary Trimline I had picked up.  Most of the components are dated 8/68 but the production date on the finished product is 2/69.  Someone had asked for pictures and I've finally managed to get my latest computer to download from my camera.

I've taken shots of three of my Trimlines:  The green one, a rotary white one dated 6/73, and an early Touchtone with round buttons of later '70s vintage.

The pictures below will show the progression from hard-wired to modular mounting and handset cord designs, not including the final version produced after modular became the standard.

First, the green one with everything hard-wired.
Next, the rotary white one with modular mounting cord but semi-modular handset cord in satin silver (?).
Finally, a shot of a modular handset plug that's compatible with the earlier large opening in the handset.

The green phone and the touchtone both have lamps for the dial/pad, but they aren't the same type.  I forgot to take pictures, but the lamp on the green phone is small and at the extreme left.  The divot in the metal cover seems to fit into a divot in the bulb.  I presume this one is incandescent.   The green cover over the lamp assembly has the Bell System verbiage rather than the Trimline logo.

The touchtone has a long bulb with a metal sheath and is mounted across the opening.  It has a filament.  Unfortunately, even if it doesn't require  6V adapter, the wall-mount DSL filter has contact points for only two leads.  I don't know if it's possible to convert the touchtone over to an LED lamp, and would appreciate any advice on wiring schemes if it can be done.

[jsowers]

Thanks for posting your Trimline pictures.

Let's get a couple definitions out of the way first...

Modular means the cable can be disconnected with a plug that has a clip.

Hard-wired means the wire connects with spade lugs or bare wire (as in station wire).

All Trimlines are modular in that they have modular connections for both cords. The first Trimlines were large modular and used large plugs on the handset and mounting cord. They have either metal or plastic clips for removal. The early mounting cords did have spade lugs on one end, the end that connects to the wall. So that mounting cord is hard-wired to the wall, but not the phone.

Your second phone looks like it may have a replaced coil cord. Usually the early Trimline coil cords matched the color of the phone.

There were adapters that fit the large modular handset jacks on the handset and base and turned them into jacks like a regular modular phone would have. That's what you're calling adapted modular and that's fine. But it was modular before it was adapted too. I'm not sure about the base conversion. I think it had to be changed inside the phone and usually that happened at a refurbisher. Someone may also make adapters for the base too.

About the DSL filter, you just need to use a modular duplex adapter, meaning an adapter that has two jacks and one plug. It makes one jack into two. Plug the plug of the adapter into the DSL filter at the wall and then plug the phone and the 6 volt AC adapter into the two jacks and you should have voltage where you need it. It won't go to the filter because there are no wires there for yellow and black. But it will go through the adapter to the phone.

There's also an adapter that has three jacks in it that would work for this purpose. They made modular jack equipped 6 VAC adapters that plug right in with a modular cable, but you could use a modular to spade mounting cord with spades on one end and a modular plug on the other and use an older type AC adapter instead. As always, lamp voltage is on yellow and black wires only. Tape up the red and green spades of that cord separately or cut them off so they don't short.

I just wanted to clear up what was meant by "modular" in case anyone was confused. I hope I haven't added to the confusion!

[rp2813]

Thanks for the clarification.  I was using the term "modular" as it applies to the subscriber's ability to plug in/unplug/change out mounting and handset cords.   In the broader sense, yes, all three sets pictured above are modular in how their cords connect.

I did do some switching around with the white phones.  I needed the plug adapted for regular modular off of the white rotary set so I could put an extra long handset cord on the wall phone, so the rotary got the standard length silver handset cord with large modular plugs.  All three phones had been kicking around in a box with other phones and parts, but I decided to replace a cheap desk/wall-mount Chinese Trimline knock-off with the real thing due to poor reception and transmission quality.

I can't change the mounting plate for the wall phone.  The phone's base has one of those protruding modular plugs that slides up and down, which is designed to work with a mounting plate that has a protruding receptacle.   I'll accept the lamp not working since it would be a sloppy look if I were to run an exposed 6V pair of wires to the phone, which with the current mounting plate is the only option.