Modems and external dialers.

[Fred Cisin]

On Wed, 5 Jun 2019, Grant Taylor via cctalk wrote:
> I have this mental picture, which I think is based on something I've 
> seen at some point in the past, that was a device that attached / 
> actuated / ??? a traditional rotary dial phone.  As in it had a finger 
> that interfaced with the dial and something that could rotate it to 
> dial the digit in question, rewind (term?), and dial the next digit in 
> question.

Typically a thick flat disk that clipped to the dial, with a motor and a 
clutch to permit the dial and disk to return to rest position.
But, a FINGER is such a better visual image!

Prior to Carterfone V Western Electric, (1968) . . .
There were DAAs RENTED by TPC ("The Phone Company" (cf, "The President's 
Analyst")), dialers RENTED by TPC, and acoustic couplers in the 
after-market.

There were devices that sat on top of the "hook" of the phone (where the 
handset rested to hang up, with the handset on top of them.  A solenoid 
could lift the handset for "off-hook", and set it down again for hang-up.
In some cases, such as answering machines, that sandwich in between the 
phone and handset had speaker and microphone, but I don't recall ever 
seeing a modem made that way - "common sense" held that you needed "cups" 
for the handset for noise isolation.

Carterfone was extremely significant as it allowed connecting to the phone 
line "if it did not damage or interfere with normal operations".
Carter started trying to peddle his systems in 1959, but AT&T 
So, Carterfone is to thank for all direct connect telephone devices, 
indeed, all "foreign attachments", even a plastic cup that clipped on the 
phone handset for a little more privacy!
AT&T rejected ANYTHING that connected, on the grounds that even that 
plastic privacy cup degraded the quality of the sound.
http://www.historyofcomputercommunications.info/Book/1/1.2CarterfoneATT_FCC48-67.html

Prior to Carterfone, you had acoustic couplers, switch-hook solenoids, 
DAAs RENTED by TPC, and only TPC dialers. Once direct connection was 
available, you got things like the PhoneMate dialer, and moving piece of 
mylar with marks and photocells.

Later, "Touch tone" made it possible to "dial" by making noises into the 
phone, both simple dialers (cf. Hayes "ATDT") and simple devices to 
implement the full set of DTMF tones (cf. blue boxes, and DTMF C-tone to 
turn off FBI phone recording taps)

"Hayes Compatible" was a marketing term to describe anything that used the 
same (orsimilar) commands as Hayes.  But, Hayes, themselves, never fully 
created a standard.  Joe Campbell ("C Programmers Guide To Serial 
Communications", "The RS232 Solution", etc.) once consulted for Hayes to 
try to help them make such a standard out of the myriad devices they 
already had extant.

--
Grumpy Ol' Fred     		cisin at xenosoft.com