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54 500

Started by AL_as_needed, April 13, 2016, 08:33:31 PM

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AL_as_needed

Older 500 up for auction at goodwill, paired with a 2500. I'm passing over this one, figured I'd let ya'll in on it. Play fair.
TWinbrook7

TelePlay


AL_as_needed

Yes, that would be them. Not sure what the third piece is though, title says 3pc, I only count two phones...
TWinbrook7

AL_as_needed

Well this is sad to admit, but I ended up with these two. Looks like the little devil on my shoulder won out in the debate.....time to look for a 426a tube in the box O stuff.
TWinbrook7

Greg G.

The bottom says it's a 501, how is that different?
The idea that a four-year degree is the only path to worthwhile knowledge is insane.
- Mike Row
e

AL_as_needed

It's a party line set version of the 500.
The 501 is more or less identical to a 500, with the addition of an electronic tube (vacuum tube) in the ring circut, I presume to act as a means to vary the ring voltage to allow more sets on a given phone line. Could be mistaken though, I'm not well versed in the 501 .....yet. BSPs I have skimmed weren't too clear on their specifics.


But hey, two for ten, ill bite haha.
TWinbrook7

unbeldi

#6
Ringing bridges with electron tubes are used for four-party fully selective service, that means each of the four parties on the line can be rung individually without code ringing.  However, with code ringing these sets could also be used on eight-party lines, which was called semi-selective service.

A normal party line without code ringing can only accommodate two parties, one ringer connected to the ring side and one connected to the tip side, with the return being earth ground.

Four-party service was accomplished with polarized superimposed ring current, so on tip and ring each was a positively and negatively polarized set.  The electron tube is a cold-cathode tube that acts exactly like a diode, conducting only in one direction.  By reversing the diode between the two set on one line side, the two ringers could be rung individually when the ringing polarity was inverted.

Using tubes also has the advantage of providing a balanced line even when there were not the same number of ringers on each line side, because the impedance of a tube is essentially infinite when not triggered, in contrast to a ringing bridge with a capacitor, the normal setup.

The 501B telephone was the second type produced in the 500-line starting in 1950.


andre_janew

When I first got my landline, a computer chip was used and the chip was inside the box mounted on the side of the house.  There was also a switch inside the box.  The 1 position was for private line and the 2 position was for party line.  I know this because the chip failed on me and I had to use a neighbor's phone to report the trouble as I could receive calls, but couldn't dial out.  They went from tubes to chips.

AL_as_needed

What year did they start to make the switch from tubes to chips?

I know most 501 sets were more or less converted back to 500s and the tubes removed when party line service was phased out.
TWinbrook7

WEBellSystemChristian

Quote from: AL_as_needed on April 18, 2016, 02:25:40 PM
What year did they start to make the switch from tubes to chips?

I know most 501 sets were more or less converted back to 500s and the tubes removed when party line service was phased out.
The tube was only used for sets on a party line. Party lines within the Bell System were phased out by the late fifties, and thus, the 501 was discontinued.
Christian Petterson

"Whether you think you can or think you can't, you're right" -Henry Ford

Weco355aman

Party lines were still in use until the mid 1980's on the west coast. I was on a 4 party line as well as about 1/3 of the rural areas in Oregon, Montana, Washington
and Nevada that I knew about. Weco made a Electronic unit that supported all of the Party line phones located on the customer premises. It was a 28A ringer isolator mounted at the Protector, then wired to the ringer on the yellow lead. The ringer isolator wired according to the party for that customer. T+ R+ T- R-. The ringer inside of the phone was connected to the Tip or Ring and switched ground. It was not recommended to mix tub's and ringer isolators on same line. The ringer isolator had a opto isolator inside it. It would switch the ground ON for that party during ringing.     
Phil

andre_janew

I think they had party lines in use in the midwest until the mid 1980s as well.  The Enhanced 911 system came in and party lines went out.

poplar1

Ben, who told you they were all gone by the 1950s?

I  had a 2-party line from a 2BESS C.O. in Lithonia, GA installed in Sept, 1988. (Southern Bell)

I had a 2 Party Line from a #5 Crossbar C.O. in E. Gadsden, AL installed in July, 1986. (South Central Bell). This one had a device installed in the ONI (outside network interface) to permit use of standard phones. (I don't recall having to rewire the sets. Kept the device when I moved, but have no idea where it is now. I think it may have disconnected the phone if the other party's phone was ringing.)

I was the Tip party on a 2FR line on a DMS-100 (418 647) à Québec from 1982-1983. (Bell Canada). This required wiring the sets for Tip Party ID; otherwise, the other party would have gotten  the bill for any toll calls I made.

And my first 4FR -- semi-selective, so no tubes, just a R-500DR-3 set -- installed on a Step-by-Step line in 1968. (Southern Bell)
"C'est pas une restauration, c'est une rénovation."--François Martin.

WEBellSystemChristian

#13
Quote from: poplar1 on April 18, 2016, 06:57:44 PM
Ben, who told you they were all gone by the 1950s?

I  had a 2-party line from a 2BESS C.O. in Lithonia, GA installed in Sept, 1988. (Southern Bell)

I had a 2 Party Line from a #5 Crossbar C.O. in E. Gadsden, AL installed in July, 1986. (South Central Bell). This one had a device installed in the ONI (outside network interface) to permit use of standard phones. (I don't recall having to rewire the sets. Kept the device when I moved, but have no idea where it is now. I think it may have disconnected the phone if the other party's phone was ringing.)

I was the Tip party on a 2FR line on a DMS-100 (418 647) à Québec from 1982-1983. (Bell Canada). This required wiring the sets for Tip Party ID; otherwise, the other party would have gotten  the bill for any toll calls I made.

And my first 4FR -- semi-selective, so no tubes, just a R-500DR-3 set -- installed on a Step-by-Step line in 1968. (Southern Bell)

I (Christian ;) ) have never seen a 501 later than 1956 1957, and I thought I had read somewhere that they were discontinued by 1959. I never knew party lines existed past the '50s, but I guess there was no reason for them not to!
Christian Petterson

"Whether you think you can or think you can't, you're right" -Henry Ford

andre_janew

The 501 model may have been discontinued by 1959, but the party lines weren't.  There may have been a party line version of the 500 after 1959, but it probably had a different model number, something other than 501.