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sidetone vs anti-sidetone

Started by HarrySmith, June 19, 2011, 11:57:37 AM

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HarrySmith

I have been seeing these two terms since I got involved with phones but I have no idea what they mean. Since I was primarily focused on 500's it was not an issue but now that I am getting a few older phones with subsets apparently it is something I need to consider. Can anyone explain this simply? Remember I am not an ex Telco employee nor an electronics person so think of it as explaining to a child. Thanks ;D
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

cihensley@aol.com

The military manual that Bill Gerts recommends has a good explanation.

Chuck


dsk

Sidetone is when you hear your own speech, anti-sidetone is trying to reduce the volume you hear from own transmitter. This makes the conversation more easy, and makes people to adjust their own voice level to a comfortable level.

dsk

Adam

#4
Yes, some small amount of sidetone, like you get on an anti-sidetone set, is still important, so that the user of the phone knows the phone is working.

It's interesting to note that if you Google "sidetone", you will see discussions about how cell phones have to artificially add sidetone to the way they function, so that people won't think their phone is dead and/or keep annoyingly saying "can you hear me now?"

The 500 set was the first American set to have self-compensating anti-sidetone.  On older phones, a phone that was closer to the Central Office would have a louder sidetone because of less loop loss.  The circuit in the 500's network compensates for that and makes the sidetone appear approximately the same on either long or short phone loops.

By the way, the most common way to hear your own sidetone is to use the old telephone installer/repairman trick of gently blowing on the transmitter.  It's a sound you can barely hear normally, but it's artificially loudly reproduced by the phone's transmitter, and you hear it very plainly in your sidetone.  For an installer/repairman, this simple action at once verifies both your transmitter and your receiver are functioning properly.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

Wallphone

From what I have read about anti-sidetone, the reason it was invented was because with sidetone your own voice was so loud in your ear that you would naturally talk softer but then the other person would have trouble hearing you. By feeding only a certain amount of your voice back through your receiver, you would talk at a more normal level so the other person could hear you fine without you blasting in your own ear.
Doug Pav

Phonesrfun

Quote from: Wallphone on June 19, 2011, 02:10:42 PM
From what I have read about anti-sidetone, the reason it was invented was because with sidetone your own voice was so loud in your ear that you would naturally talk softer but then the other person would have trouble hearing you. By feeding only a certain amount of your voice back through your receiver, you would talk at a more normal level so the other person could hear you fine without you blasting in your own ear.
Doug Pav

A second and equally important feature of antisidetone is that with the older (sidetone) sets using the phone in a noisy office or factory was very difficult.  All the noise and other sounds that were in the same room as the user would be so loud in the receiver that the person using the phone could not hear the person on the other end.
-Bill G

deedubya3800

I can definitely attest to that as I used to work in a restaurant that had a very modern multi-line telephone system, but the sidetone on the sets was horrendous! It made hearing some customers nearly impossible. I eventually developed a technique of covering the transmitter with a card when I wasn't speaking to block the dining room noise from looping back, and flip it up with my fingers when I was talking. Irritating, but it worked and that was all I had at my disposal without a PTT handset!

Darkstar2006

I am new to old phones and I guess I am more an enthusiast than a collector. So when I found a 51C candlestick with no wires, even with all, and sometime too much info, I had a problem wiring it to a subset.

My 51C had a RR terminal on the stack and needed a 5 wire subset cord. (there might be a work-around) so I looked for a subset w/RR terminal. All of the info said it should be connected to a 554C subset (sidetone) I could not find a picture of what it looked like. (looks like any other metal box subset only the guts are different).So I used a 684bc (anti-sidetone it had an RR terminal) and after doing some unusual wiring it worked beautifully as an active phone in my living room.

Not good enough! I found a 554C at an auction recently and hooked it up to the 51C and I hate it. 

Sidetone v. anti-sidetone- 
The 684BC made the receiver sound silky and the phone easy to use. The 554C is loud and annoying and I hate it...but for collecting they will stay paired.

Life Observations -"Fantasy imitating life" department.
Have you ever noticed that the actors in old movies, even though the phone was a prop phone, when using a candlestick hold the receiver at a slight angle. Is this for a better camera shot or is it because this was a natural way people handled the sidetone phones of the day?
I know it works for me.
Why do people with cell phones use "old phone" as their ring tone?

-Dave S.