[GreenKeys] The Milliwatt Supply...

Tue Feb 17 22:19:18 EST 2009

The DAA's brought a lot of "special service" installers to their knees.
The modified wiring of the associated telephone (there was usually
a gray phone connected to the little box) drove the less-technically-inclined
installers crazy. These were the same people who installed and maintained
Teletypes (supposedly). I often had to go out after a new
installation bombed out to rewire the phones since the original installer
had told the customer "I'm used to working on much more complex
things..." and then he just left with the thing not working! I followed this
particular guy around for months...he was my "overtime maker".

Another issue with the DAA's...they had mercury relays and so they had to be
installed on a wall (vertically). In those days double-back sticky tape
was the rage and the stuff had a tendency to let go...so the DAA would fall off the
wall, the relay would close and the CO would see a shorted line and cut off
the service. With the "new" electronic switching CO's it was often a real
struggle to get the dialtone back on!

I remember seeing privately-owned Model 33's with modems hooked up
to the DAA's.

BTW...the DAA was the "legal" way to hook up something to the 
telephone lines. It provided an impedance match/isolation and an
incoming ringing signal contact closure to the customer's equipment.

-------------- Original message from Peter Gottlieb <nerd at verizon.net>: -------------- 

> A lot of COs had -9960 as the milliwatt reference, including the one 
> where I lived. I was one of the first to order an interface to the 
> phone lines, they called them DAAs back then, "Data Access Arrangements" 
> and the installer who came had no idea how to determine the line loss. 
> I was just a teenager and told him how to do it and he hung out for a 
> long while playing with the various test sets they gave him but for 
> which he wasn't trained. I showed him how to use them all and we 
> followed the BSP to get everything set up properly. I remember him 
> "accidentally" leaving a good assortment of stuff from his truck for me. 
> 
> The milliwatt number didn't just give you 1004 Hz, it ramped up when you 
> called it if it hadn't been called in a while. It would start way down 
> at maybe 2-300 Hz and go up to 1004 in about a second or two. 
> 
> Those old mechanical switches had personality. 
> 
> Peter 
> 
> 
> Jack wrote: 
> > 
> > I’m not sure if the milliwatt numbers are still available for 
> > installers to call into, 
> > 
> > but the “call back” numbers are still used. 
> > 
> > There was also a number that we called into for “Quick Brown Fox...” 
> > to be sent 
> > 
> > to a dial up TTY...there was a separate number for the TWX service (a 
> > 510-XXX-XXXX 
> > 
> > dedicated Area Code in NY/NJ that’s long reused fro telephones). 
> > 
> > I worked for a small electronics company 
> > 
> > before joining Ma Bell and we always called the QBF line to test our 
> > 
> > acoustic modem products and the repackaged Teletype Model 33 TTY’s we 
> > sold with 
> > 
> > them as “portable terminals”. 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > *From:* greenkeys-bounces at mailman.qth.net 
> > [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of 
> > *TELEGRAPHER at att.net 
> > *Sent:* Tuesday, February 17, 2009 12:09 PM 
> > *To:* Don Robert House; greenkeys at mailman.qth.net 
> > *Subject:* Re: [GreenKeys] The Milliwatt Supply... 
> > 
> > 
> > 
> > In addition when techs were sent to the field they sometimes needed 
> > the same source of 1004 kc tone. WECO made a portable unit 
> > specifically for that purpose J94071B Milliwatt Reference Generator). 
> > It supplied 1004 cycles at either 600 or 900 ohms impedance's. I've 
> > got one here. Anyway it was battery powered and calibration was 
> > checked with a portable meter that was used with it (J94023D 
> > Transmission Measuring Set). It reads levels in either 600 or 900 
> > ohms. It was also used with some switching test sets in the CO. I've 
> > got one of them also and use it occasionally to verify some of the 
> > levels around the shack here. Nice little portable meter with no 
> > batteries or ac/dc power needed. 
> > 
> > As an added sidenote, just what you all wanted to read, back in the 
> > 70's we had a series of numbers that we could call from the field that 
> > would give us, time of day, a MW reference level tone and gobs of 
> > others for testing lines. One of the neat ones was a ringback number 
> > that we would call after a telephone installation, hang up and then 
> > wait for it to call you back. Particularly useful on 2 and more party 
> > lines. If you didn't gt a call back and you were on a 2 party line, 
> > you had to redo something. With some two pary lines it wasn't just a 
> > matter of flipping the T-R connection. You had to go in and rewire 
> > the set to give the office a different ground value to see. What a 
> > pain that one was. 
> > 
> > Enuff! 
> > 
> > Larry 
> > W0OGH 
> > 
> > 
> > 
> > 
> > -------------- Original message from Don Robert House 
> > : -------------- 
> > 
> > 
> > > I am spending too much time on this list. 
> > > 
> > > With the latest pains in my ear and throat I am bound to write 
> > > something incorrectly... 
> > > 
> > > Sigh... 
> > > 
> > > Deci = 10 Bel= named after Alexander G. Bell 
> > > 
> > > 1004Hz at 1 milliwatt into 600 Ohms 
> > > 
> > > This is a standard reference for over 100 years for voice message 
> > > circuits. 
> > > 
> > > One of these reference milliwatt supply is available in just about 
> > > every CO in the USA. 
> > > 
> > > Over copper wires, carrier systems, lightwave or whatever. 
> > > 
> > > Why did I have to dream about this last night... 
> > > 
> > > If you want to know more look it up in the Green or Red books... 
> > > 
> > > I guess you guys are getting to me. 
> > > 
> > > Don 
> > > K9TTY 
> > > ______________________________________________________________ 
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