Re: [GTALUG] mysterious restarts
On Jun 26, 2016 12:14 PM, "James Knott via talk" <talk@gtalug.org> wrote: <snip>
I don't know what power is provided on dry loops, but I believe there's still "battery" on the line. On a
You put the word battery in quotes. Perhaps you mean a Rogers valve? I think that's how the patent names it. When I was a kid every corner store had a tube tester for DIY repairs. Anecdotally I remember CFRB as Canada's First Rogers Battery? The Rogers valve was what allowed a radio to run on home current. regular phone line, if the device
draws enough current, the exchange will consider the line "seized" and not send ringing current on it. If not enough current is drawn, then ringing is possible.
I don't know for sure myself. I always assume the last quarter mile is analog, but that may have changed for newer condo and residential home development.
What's generally referred to as the "last mile" can be anything from right next door to several kilometres. For examples, in an apartment I used to rent, the exchange was just a block away. Here, a couple of blocks. When I was a kid, growing up in Oakville, it was about 3-4 Km and it may be much further elsewhere.
BTW, many years ago, before amplifiers, it was possible to make a call from New York to Colorado, before it became too weak.
Wow you look a lot younger in your picture. :-)
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On 06/27/2016 09:12 AM, Russell Reiter wrote:
On Jun 26, 2016 12:14 PM, "James Knott via talk" <talk@gtalug.org <mailto:talk@gtalug.org>> wrote: <snip>
I don't know what power is provided on dry loops, but I believe there's still "battery" on the line. On a
You put the word battery in quotes. Perhaps you mean a Rogers valve? I think that's how the patent names it. When I was a kid every corner store had a tube tester for DIY repairs.
That's what it's generally called. The power comes from rectifiers, with batteries float charging. It's nominally -48V, but actually about -56V
Anecdotally I remember CFRB as Canada's First Rogers Battery?
Batteryless. Prior to that, vacuum tubes required batteries to power the filament (heater), as there was no separate cathode. With a separate cathode and filament, it became possible to use AC power for the filament, generally provided by a transformer.
The Rogers valve was what allowed a radio to run on home current.
Actually, it allowed the tube filaments to run on AC. The rest of the radio was quite capable of running on household AC, after rectification and filtering. Back in those days, you'd have an AC powered radio, with a battery used only for the filament. Going way back, there were indeed separate batteries for the high voltage applied to the plate, low voltage for the filament and, in some cases, even the grid, which required a negative bias voltage. As technology advanced, it was possible to add a resistor in the cathode circuit to create the negative bias on the grid, then the separate cathode and filament allowed getting rid of the filament battery.
regular phone line, if the device
draws enough current, the exchange will consider the line "seized" and not send ringing current on it. If not enough current is drawn, then ringing is possible.
I don't know for sure myself. I always assume the last quarter mile is analog, but that may have changed for newer condo and residential home development.
What's generally referred to as the "last mile" can be anything from right next door to several kilometres. For examples, in an apartment I used to rent, the exchange was just a block away. Here, a couple of blocks. When I was a kid, growing up in Oakville, it was about 3-4 Km and it may be much further elsewhere.
BTW, many years ago, before amplifiers, it was possible to make a call from New York to Colorado, before it became too weak.
Wow you look a lot younger in your picture. :-)
I have long been interested in the history of telecommunications, an industry where I have spent most of my career.
On Jun 27, 2016 9:25 AM, "James Knott via talk" <talk@gtalug.org> wrote:
On 06/27/2016 09:12 AM, Russell Reiter wrote:
Wow you look a lot younger in your picture. :-)
I have long been interested in the history of telecommunications, an industry where I have spent most of my career.
My first contact with the electrical field, pardon the pun, was at the Ontario Science Center in 1967 when it opened. Apparently I have the best hair for demonstrating static electricity with a Van der Great generator. I did it so often that my next real contact with the field was many years later. One of the student demonstrators grounded out my butt with the ground rod. Tasted like 30,000v @ 10kv/cm through air. I was then invited to the staff Christmas party and was pied in with a shaving cream pie as "one of the gang."
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Russell Reiter