Author Topic: Phone plug help needed  (Read 2563 times)

0 Members and 1 Guest are viewing this topic.

Offline Shock

  • Super Contributor
  • ***
  • Posts: 2259
  • Country: au
Phone plug help needed
« on: April 24, 2014, 05:01:43 pm »
Anyone know anything about these phone plugs?

Am looking up a suitable replacement for the WECo 310 and the HP manual shows it also as a PJ-051R.
The top plug (3 conductor) is labeled both PJ-051R and M642/2-2 (which I assume is the military spec).
The bottom Pomona plug is labeled a WE 310 to BNC (2 conductor, does not employ the sleeve).

I have two questions:

1. The top plug looks like it has two separate conductors at the ring compared to the pomona, what is this? Is the Pomona plug correct or is this a difference in specs?

2. I was going to make a dual purpose patch cable (audio frequencies) for balanced and unbalanced use. Is there any benefit in using all 3 "conductors" and chassis ground the shield to the instrument end only?
Should I be using twisted signal cables for the balanced or will a double shielded coax be the thing?

Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM
Oscilloscopes: Rigol DS1054Z, Phillips PM3065
 

Offline fcb

  • Super Contributor
  • ***
  • Posts: 1246
  • Country: gb
Re: Phone plug help needed
« Reply #1 on: April 24, 2014, 08:46:34 pm »
Anyone know anything about these phone plugs?

Am looking up a suitable replacement for the WECo 310 and the HP manual shows it also as a PJ-051R.
The top plug (3 conductor) is labeled both PJ-051R and M642/2-2 (which I assume is the military spec).
The bottom Pomona plug is labeled a WE 310 to BNC (2 conductor, does not employ the sleeve).

I have two questions:

1. The top plug looks like it has two separate conductors at the ring compared to the pomona, what is this? Is the Pomona plug correct or is this a difference in specs?

2. I was going to make a dual purpose patch cable (audio frequencies) for balanced and unbalanced use. Is there any benefit in using all 3 "conductors" and chassis ground the shield to the instrument end only?
Should I be using twisted signal cables for the balanced or will a double shielded coax be the thing?



1. Not sure why it appears to have 4 conductors, it probably doesn't use 4 conductors.
2. Use twisted pair if you can - especially if you using balanced electronics. If you're not using balanced electronics then it won't matter much. As for grounding - that is a more complex question, and will be very dependent on your system design.

BTW:  These jacks are called 'bantam jacks'.
 

Online Richard Crowley

  • Super Contributor
  • ***
  • Posts: 3862
  • Country: us
  • KE7GKP
Re: Phone plug help needed
« Reply #2 on: April 24, 2014, 09:04:23 pm »
1. The top plug looks like it has two separate conductors at the ring compared to the pomona, what is this? Is the Pomona plug correct or is this a difference in specs?
That extra metal "ring" was provided for long-term, heavy-duty protection in telephone switchboard use. Where those plugs were inserted and pulled out perhaps hundreds of times every day. (Back before the days of automated phone systems where the user would dial the number for themselves and relays would make the proper connection.)
The extra metal ring was not electrically connected to anything.

Quote
2. I was going to make a dual purpose patch cable (audio frequencies) for balanced and unbalanced use. Is there any benefit in using all 3 "conductors" and chassis ground the shield to the instrument end only?
Should I be using twisted signal cables for the balanced or will a double shielded coax be the thing?

We commonly use ordinary "mic cable" which is flexible, shielded, twisted pair. It is customary to connect the shield at both ends of a patch cable, and implement whatever ground-lift, etc. in the wiring between the patch bay and each piece of equipment. The whole area of shielding and grounding is a very sticky wicket with galaxial political ramifications.

That is a "long-frame" switchboard/patchbay version of a 1/4 inch phone plug.
Bantam phone plugs are a smaller variety, not interchangeable with the model you show in the photos.
« Last Edit: April 24, 2014, 09:09:27 pm by Richard Crowley »
 

Offline Shock

  • Super Contributor
  • ***
  • Posts: 2259
  • Country: au
Re: Phone plug help needed
« Reply #3 on: April 24, 2014, 09:26:03 pm »
BTW:  These jacks are called 'bantam jacks'.
That is a "long-frame" switchboard/patchbay version of a 1/4 inch phone plug.
Bantam phone plugs are a smaller variety, not interchangeable with the model you show in the photos.

Yes I was about to say the Bantam seems a different beast, 4.4mm diameter not 6.35mm on the WE 310, PJ-051R.

Thanks for the info. I have looked at how the jacks/sockets work and that makes sense.
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM
Oscilloscopes: Rigol DS1054Z, Phillips PM3065
 

Offline fcb

  • Super Contributor
  • ***
  • Posts: 1246
  • Country: gb
Re: Phone plug help needed
« Reply #4 on: April 28, 2014, 07:39:33 pm »
BTW:  These jacks are called 'bantam jacks'.
That is a "long-frame" switchboard/patchbay version of a 1/4 inch phone plug.
Bantam phone plugs are a smaller variety, not interchangeable with the model you show in the photos.

Yes I was about to say the Bantam seems a different beast, 4.4mm diameter not 6.35mm on the WE 310, PJ-051R.

Thanks for the info. I have looked at how the jacks/sockets work and that makes sense.
Quite right - spent to much time recently playing with bantams.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf