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Back to Basics Telephonically
10-03-2015, 05:30 AM (This post was last modified: 10-03-2015 05:35 AM by Adam Vaughn.)
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RE: Back to Basics Telephonically
(09-30-2015 07:15 AM)Martin Hepperle Wrote:  
(09-30-2015 05:50 AM)Adam Vaughn Wrote:  ...
Note what's different about the keypad... Wink

Indeed that's one of the things that can drive me crazy: When I have to dial into a phone conference from my PC I have to use the digits on my computer keyboard (for screen sharing) as well as on the phone (for the sound).
Guess how often I mistype a digit...

Difficult to understand why there is no standard layout for numeric keypads, now that we have standards for almost everything!


The Bell System (aka AT&T) did a lot of research on key layouts when developing the Touch-Tone dialing system. Numerous different layouts were tried, with the one used on most modern touch-tone phones (123/456/789/[*]0[#]) worked better for folks than the 'adding machine'-type layout. More info can be found here. As for what I was referring to, see below.

(10-01-2015 02:27 AM)BobVA Wrote:  
(09-30-2015 05:50 AM)Adam Vaughn Wrote:  Note what's different about the keypad... Wink

I've never seen a Touch Tone phone without a modular handset connector, so I'm guessing this was a very early TT phone? Model 1500?

And the lack of the * and # are obviously because those esoteric keys were reserved for NASA to communicate with TelStar? :-)


PS I have a Model 2500 connected to my VOIP interface. Surprisingly it can ring it!

They're not especially common, but hard-wired (non-modular) TT sets are out there. I believe the modular connector was first field trial-ed by the Bell System in the early '70s, and then integrated into the production lines as the decade progressed. I've also seen phones which were half-converted to modular in the field; that is, they still have a hard-wired handset cord, but have been crudely fitted with a modular line cord by way of a small modular jack inside the phone base.

Yep, it's a 1500. You don't see them very often nowadays, but it is the most common of the 10-button phones. I also have a pair of 10-button Trimline phones (1220), which are probably the hardest to find of the early TT sets since they were only produced for a year or two before the addition of the asterisk (*) and octothorpe (#) buttons.

And speaking of special signaling, have you ever seen a 16-button touch-tone dial?
[Image: autovon1.jpg]
It was intended to go with the AutoVON system used by the government and military to ensure that important calls were able to get through in times of crisis. The four buttons in the right-hand column were used to assign a call a certain level of precedence. The FO ("Flash Override") function was reserved for the President and other high-ranking officials in order to make absolutely sure that important calls got through in an emergency. It's since been replaced by other systems, so I couldn't actually use it to override other people's phone calls these days, but it's certainly neat. Cool
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Messages In This Thread
Back to Basics Telephonically - Gerald H - 09-22-2015, 04:00 PM
RE: Back to Basics Telephonically - vk6ti - 10-02-2015, 12:34 AM
RE: Back to Basics Telephonically - Adam Vaughn - 10-03-2015 05:30 AM
RE: Back to Basics Telephonically - BobVA - 10-01-2015, 02:27 AM
RE: Back to Basics Telephonically - Mark - 10-01-2015, 04:13 PM

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