ECN Forum Forums General Topics of the Trade Voice - Data - Video Discussion How could this be done legally???

I have a Western Electric 500 set dated 1962 and that has just a 3-conductor red/green/yellow cord fitted for such use.

I also have a Princess phone with the lamp wired to yellow/black. The lamp feed actually goes via a series resistor which is shunted by a pair of hookswitch contacts so that the lamp runs runs dimly when the phone is on-hook (there is also a cut-off switch in series with the resistor to turn off the "night light" feature).

As I understand it the original power units employed for these phones had relatively high-impedance secondaries to limit the current in the event of a short or cross with the red/green C.O. pair.

I still have a couple "princess" wall warts around here somewhere. (Ma Bell beige)

Telecom/ITE standard UL60950 requires Reinforced insulation between a 120v primary circuit and a TNV circuit (POTS is TNV3). Reinforced insulation requires a distance through insualtion of 0.4mm. I think the protective sleeve just ensures this .4mm requirement is met without relying on the existing phone wiring - probably a good idea.

One thing that really caught my eye was the statement, "This product is compliant with UL 1863, UL 60950, FCC part 15 Sub-part B class B and FCC part 68". "Is compliant" could be taken to mean "listed to"...or not. I know from experience with one NRTL, there are certain types of products that the particular NRTL (that shall remain nameless) will not give a listing to, even though the product may meet all applicable safety requirements. Some things just make some people too nervous.

OK, somone buy one of these so we can check it out! Just kidding, but I would be curious to see if it has any safety/NRTL marks. If it was submitted for TIA/EIA/IS-968 (formerly FCC part 68) then there should be a traceable ID number on the product somewhere.

Neat product though.

I saw a dual compartment "old work" box the other day at the BORG that would allow 120v and LV in a double wide cover. The line voltage side was full sized and the difference was made up on the LV side