Modems and external dialers.

[Eric Smith]

On Wed, Jun 5, 2019 at 11:38 AM Fred Cisin via cctalk <cctalk at classiccmp.org>
wrote:

> 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.

[...]

> 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.
>

The 1968 Carterfone decision did eventually result in customers being
allowed to hook their own devices up directly to the phone line, but
contrary to what a lot of online sources including Wikipedia claim, that
didn't really happen until the FCC promulgated the Part 68 regulations in
1975.  The immediate reaction to Carterfone was that in 1968 Bell created a
"foreign attachment" tariff, which allowed customers to lease the type CBS
or CBT Data Access Arrangements (DAA), which included protective coupling
circuitry, and connect their own devices to the network only indirectly
through the DAA.

Starting in 1975, equipment could be sold for direct attachment if it met
the Part 68 requirements and was registered with the FCC. The equipment had
to bear a label with the Ringer Equivalency Number (REN), and the
subscriber was supposed to notify the phone company of the RENs of the
devices they were using. I don't know anyone who actually did so.

There is very little detail on this available online, but I found that
Google Books can show relevant excerpts from _Communciations Law and
Practice_ by Stuart N. Brotman, 2006 printing (originally published 1995).
See pages 5-19 and 5-20.