***** Moderator's Note *****
>
> There were a variety of interface devices that were made available
> after the FCC mandated interconnection. I'm most familiar with the
> CDH, which was intended to connect POTS lines to customer provided
> equipment. It did the job, but it was too complicated: not only did it
> have separate supervision leads that were isolated from the talk path,
> but it had separate ringing leads as well. There might have been PBX's
> or other CPE which could access the CDH directly, but ordinary key
> equipment could not: to use it for CPE key equipment, you needed
> _another_ interface to match the CDH interface.
>
> Ma Bell had too many interfaces and they cost too much to install and
> rent: it was inevitable that the FCC would dictate type-acceptance and
> allow direct connections. I don't remember when that happended, but it's
> been the norm ever since.
Yes Bill, but that doesn't help with stuff that is not type accepted. Isn't the new term of art certified? I'm trying to devise a way to patch the PSTN incoming calls to manual switchboards that predate customer dialing. If you connect the interconnect terminals of some of those boards it will look like an off hook condition to the PSTN.