News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

What is this?

Started by persido, October 11, 2014, 04:01:34 PM

Previous topic - Next topic

19and41

Quote from: unbeldi on February 19, 2015, 02:28:43 PM
Quote from: 19and41 on February 19, 2015, 02:07:25 PM
The things I learn on this site!  I had never heard of such a problem in over 40 years of working with communications equipment.
Really?   I think, key systems in particular, exhibited noise problems frequently, because of the extensive inside wiring required, which provides opportunity to pick up RFI, but also to radiate it when produced in the system.  Even small electrical problems, like cold solder joints, that were still marginally operational for the currents they carried, could demodulate radio transmitter signals for example,  producing a 'nice' background of the local radio station in your receiver.

I has not worked with Key systems, but it is interesting to learn about the characteristics of them and the problem and corrective measures used with them.  Incidentally, I did not comment to express dismissal of the subject being discussed, quite the opposite.  I always try to post in a manner that I would also like to be posted to.  I wanted to state this, being a new person here, as my intentions are friendly.
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke

poplar1

G-Man, all  I was asking was for the source of the copied info. In searching in TCI library, I was able to find your article on cohering, where the first text above is attributed to the Bell System Technical Journal, April 1932. I'm still looking for the second part.
"C'est pas une restauration, c'est une rénovation."--François Martin.

unbeldi

I think the entire quote is on p.258 in

W.C. Jones, A.H. Inglis, The Development of a Handset for Telephone Stations, BSTJ 11(2) 245-263 (April 1932).

(attached)

andre_janew

Until reading this thread, I didn't know that such filters existed.  I have a 302 and it never had such a filter that I know of.

unbeldi

Here is a short list of the No.61 filter codes in some of the handset mountings.
The filters claim two patents:
*US 1227113 (1917, Campbell)
*US 1603305 (1926, Zobel)

unbeldi

Here is another example of a No. 61 filter.

Member ExtremeCinema just posted a picture of the 61N filter mounted on a B1 handset mounting: