1500D won't break dial tone, but only on 2 jacks.

[Greg G.]

I just realized that the 1500D we had in our bedroom won't break dial tone.  But it only does that on 2 of the 4 jacks in our house, it works fine on the 2 other jacks.  Coincidentally, the 2 jacks it doesn't work on have been installed within the last couple of years.  The other 2 jacks probably date back decades.  I don't have another TT phone, but rotaries work fine on the 2 jacks in question.

I suspect it has something to do with the way the biscuit adapter I have on the 1500D is communicating with the new jacks, i.e. the wiring of the new jacks doesn't like the biscuit adapter.  Here's a picture of the biscuit adapter.  I don't have a picture of the jacks in question, don't have time right now to see how they're wired.

[unbeldi]

I just realized that the 1500D we had in our bedroom won't break dial tone.  But it only does that on 2 of the 4 jacks in our house, it works fine on the 2 other jacks.  Coincidently, the 2 jacks it doesn't work on have been installed within the last couple of years.  The other 2 jacks probably date back decades.  I don't have another TT phone, but rotaries work fine on the 2 jacks in question.

I suspect it has something to do with the way the biscuit adapter I have on the 1500D is communicating with the new jacks, i.e. the wiring of the new jacks doesn't like the biscuit adapter.  Here's a picture of the biscuit adapter.  I don't have a picture of the jacks in question, don't have time right now to see how they're wired.

Sounds like this phone has escaped the era of polarity guards unscathed.

I am sure all you need to do is switch the red and green conductors in the two jacks that don't work, or find the origin of that wire run and switch them there.   Decades old wiring was always correct, polarity wise, but nowadays there is no guarantee that any specific polarity is installed, even at the NI.

[unbeldi]

In these cases a tool such as the one pictured here is rather handy.

This is a GTT-200 Dual Telephone Line Tester by GB Instruments of Milwaukee, WI.

It indicates whether a line jack has correct polarity, incorrect polarity, or is dead, and does so for both lines on an RJ14.

They can be had from about $5 up, if you're lucky, but should cost no more than about $9.

A polarity tester can also be built easily with a 10KΩ resistor, a couple light-emitting diodes, and some wire, but given the cost of these ready-made tools, why bother with that!

[unbeldi]

Are you using this box at the end of the line cord of your 1500, because the cord is terminated in spade lugs?

If so, then you should connect the green wire coming from the phone to the red wire in the biscuit, and the red wire from the phone to the green wire in the box, to maintain proper polarity.
A standard modular cord reverses the pin sequence from end to end.

In such case, the modular jack on the end of the line cord from the phone represents an FXO interface and therefore the wires need to be swapped.  The wall outlet is an FXS interface and the colors should match, unless the inside wiring used the newer dual color schemes, White/Blue blue/white.

[poplar1]

As you now have the adapter wired, the old Touch-Tone sets--those without polarity guards--should not dial out. When adding a biscuit adapter, with a standard modular cord going from the biscuit to the wall jack, you should always reverse the wires inside the biscuit adapter: connect green wire from phone to red terminal, and red wire from phone to green.

If you do this, then it will be the old jacks--not the two that are working now new ones--that will no longer work.  If this is a central office (land) line, the line may be  reversed before it even gets to your house, or, if not, there is a problem with the wiring of the old jacks.

With a central office line, you should be able to draw dial tone from the "ring" side (-) (red) to ground, but not from the "tip" side (+) (green) to ground.

[Greg G.]

I should have clarified that this is a POTS line, and yes, I'm using the biscuit because of the spade tips.

[Phonesrfun]

Short answer:


For the two jacks that don't work - reverse  the wires to the jacks.

[poplar1]

Short answer:


For the two jacks that don't work - reverse  the wires to the jacks.

Except that those are the two  jacks that are apparently wired right (bedroom and other new one).! And if you reverse the ones that are wired right, instead of correcting the reversal in the biscuit adapter, then later on, if you plug in a modular phone without polarity guard (2500DM, 702BM, etc.), then it won't dial out.

[unbeldi]

Well, we really only know what works and what doesn't.

What is right or wrong needs to be determined and the only way to do so is to start with the telephone set itself, or to measure voltage levels with a meter or tester (as previously suggested!).

So, why not spend a moment and open up the telephone to see whether the green and the red wire are actually on the correct terminals.

• For individual line service, the green line cord wire (TIP) should be on L1, and the red line cord wire (RING) should be on L2.
• On the bisquit, wire green to red and red to green.
• Verify your extension modular cord, which should have the sequence of pins is reversed on the ends.
• On the wall jacks that NOW don't work anymore, swap the center pins no matter what color they have.

Set it and forget it!

Ref:
BSP Plant Series, Section 502-502-101 i1 7002, Reference; 1500D and 1554B Telephone Sets

[Greg G.]

Cold rainy day on my day off, perfect for puttering around with long-neglected phone projects.  Finally got around to this one.  Swapping the red/green wires on the line cord to the biscuit worked.

[Greg G.]

... Swapping the red/green wires on the line cord to the biscuit worked.

...and then back again!  This phone is rarely used, it's in the bedroom on my wife's nightstand to use for emergencies so she could quickly dial 911.  As we were doing some cleaning, just for kicks and giggles I picked up the handset and tried to dial out, but it wouldn't break dial tone.  So....I switched the red and green wires on the line cord back to the original positions on the biscuit (red to red, green to green) and now it works again.  Go figure!   

[Jack Ryan]

The trouble with phones that don't have polarity guards is that any time a telephone tech does some work on the street your line might be reversed and the phones will no longer dial.

If the phone is really there for emergency use, fit a polarity guard or change to a phone that already has one (or uses a rotary dial).

Jack

[andre_janew]

If it were me, I would've swapped the red and green wires on the jacks that didn't work with the phone.  That way, it would work on all four jacks.

[oldguy]

Without being there to actually check things out, I would tend to agree with Bill & andre_jenew.