Telephone Ringers: how & why

Oh, I worked on the frame in the Palm Desert CO for a year, and then the Crestline CO after that, and many the time did I reach throught with a bare, sweaty arm just as someone rang through. You reach in, when ZAP! the ring voltage hits. BAM! as your arm reflexes up, and you hit your arm on the pins of the block above. OUCH! as your arm goes back down, just in time to get hit by the next burst of ring voltage... 8-)

Charlie

But do _all_ emergency dispatching centers have the capability to read and interpret a GPS signal from the cell phone? I suspect at this point in time most do not.

I believe you are _required_ to have a GPS-capable phone on the Verizon network here in Arizona, effective 1/1/2008.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave

Wow, I remember way back as a kid, one night our phone started to ring continnuously woke us all up and didn't stop even after we picked up all the phones... My dad ran into the basement and disconnected the wires...

I never knew what that was about.....till now...

So tell me how was the customer supposed to call in and report a problem if their phone is ringing continuously....?

Mark

Federal law (FCC regs) require all new activations be GPS enabled phones. Been that wayfor several years. Whether the system (e-911) can handle it ina given area is another issue!

Is there a list, table, or something that tells what phones have this ?

TerryS

Verizon has a list. I would imagine the other service providers have a list as well.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave

Take it off the hook and dial the service number?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

With a shoe on the line that has continuous ring on it? No dialtone... just a blast of loud 20 Hz in the ear.

I never worked for a LEC, and hence rarely ever worked on POTS subscriber lines, but 20 Hz continuous ringing did have other uses. Originally it was available on

2-wire testboards (18B Testboards were the ones I worked at) that interfaced with cable heads. There was a front row of cords and a back row, and one particular key labeled RING of course, could be pushed forward or backward to connect ring current to front or back cords as desired, with the cord inserted into the Primary Jack for any given cable pair one wanted to "ring".

The typical use we found for this was with a lot of the leased lines using those new fangled things called modems, instead of teletype loops (which had anything from 20ma to 60ma of current pulsing on them all the time).

Seems that every now and then a leased line with no current on it (no loop current or no teletype current) would get a static charge built up on the line, and it would simply go dead, with no continuity for the voice path. Most of the time just putting a test set on the line would clear it, but we discovered that a 100% guaranteed fix was to zap the line with a few seconds of ring voltage! So that became pretty common... until most leased lines began to be equipped with "sealing current" modules to avoid the problem.

--
Floyd L. Davidson 
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

Floyd,

That is weird. How did a static charge keep that "dry" leased line from working?

By the way -- I see you're in Alaska. Have you ever had any dealings with Witham Reeve?

Bob

What it really was, was a high-resistance splice caused by oxides on the wires. Most any voltage would "seal" it again.

"Don Bowey" wrote" [snip]

Ahhh. I see.

My POTS line gets noisy some times. Maybe because I rarely use it. The best cure seems to be to get my line to ring and then go offhook in the middle of the ringing. It works every time (for a while).

Bob

If the static charge is higher than the signal level... the continuity for signal is zilch. The real cause though is corrosion from dampness and poor insulation at splice boxes and connectors. The corrosion causes various effects (resistance, diode effects, and capacitance) that allow a charge to build up and be maintained at a higher voltage than the signal. At that point, the line goes totally dead. Usually just a lower resistance (for example plugging in a test set on the line) would dump the charge and make it work again. That didn't change the cause though. On the other hand, hitting the line with 100 VAC of 20 Hz ring voltage would often change the electrical characteristics of the corrosion, at least for awhile.

That was not something commonly experienced until the

1960's or so, but it became a very common problem with "dry" lines used for leased line modems. Today any line that does not have a DC current on it otherwise will be equipped with a sealing current module, which puts a DC current on it (usually using about 24 VDC and about 10-20ma).

Which of the 600,000 people in Alaska would Witham Reeve be? And does he live in Los Anchorage, or actually in Alaska? ;-)

--
Floyd L. Davidson 
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

Floyd,

Whitham owns and runs a telecom engineering group in Anchorage, but I think he's retired, now. He has written several books that are "bibles" for the design side of the business. Here is one of them:

...and here's his website:

He is a very knowledgeable and likeable guy. On a side note, I was watching a tv show about early Alaskan bush pilots and they spent a bit of time on a guy named Bob Reeve. It got me curious, and after a little digging on the web I learned that Bob Reeve is Whitham's father. I then started singing the Disney song "It's a Small World". 8-)

Bob

It is the oxide flim that form on the wires, but it isn't usually just high resistance in series alone that is the problem, and it would rarely be a (soldered) cable splice. Terminal boxes, with punchdown or the old screw type terminals do indeed get high series resistances, but otherwise there are the other effects shunting the line too.

It used to be that often the lack of VF continuity would be corrected by just putting a test set on the line (which would bleed off any charge on it, and perhaps even zap the corrosion in the process). Sealing current (e.g. 10-15 ma) is not a corrective measure, it prevents the oxide film from forming.

When no sealing current existed, to correct it often required the high voltage (and current) available with ring voltage, which breaks down the oxide film that has formed.

--
Floyd L. Davidson 
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

Oh, this does get interesting. I've heard of him, but have never met him. (He worked for Anchorage Telephone Utilities back in the 70's, which is where I'd heard of him.)

However, I worked for several years with a fellow whose father was in a way responsible for him being in Alaska in the first place!

The father of this fellow I worked with was the head honcho for American Airlines in Lima Peru way back when. He fired a pilot that just seemed to take too many risks (though he never crashed a plane because of it). That pilot was Bob Reeves, who went to Alaska... and founded Reeves Aleutian Air (the highest risk air routes in one of the highest risk markets that existed at the time).

And we might note too that Reeves Aleutian Air also had one of the best safety records too! The guy was *good*.

--
Floyd L. Davidson 
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

I spent some time along the Aleutian Islands in the late 50s and got to hear many stories about Reeve Aleutian Airways start and growth. I had many flights with them, two of which were hair-raisers.

Did anyone ask for a brain dump of what you may know? You didn't say anything I don't know from experience.

I know how static charge works. I recall back in the early 90's we had a freak snow storm that dumped a few feet on the city in a very short time. A friend and I worked emergency communications for the Red Cross.

When the group of us got to the radio room we discoverd that they'd cut off the cable ends on all the coax and because the storm was still blowing you could see the center conductors arcing to the ground braid on all the cables all because of static electricity.

Imagine if we could harvest and store that energy.