[TUHS] What's with the DZ-11?

[Ronald Natalie]

The original Trailblazers were special modems that on a good like could approach 19.2KB.   T  They also had special software that recognized when UUCP protocol stuff was being transfer and apportion the bandwidth and spoof the ACKS on the protocol to increase the UUCP throughput.

Believe me, running a bunch of 9600 data transfers on a DZ will pretty much saturate the unibus in a hurry.  The thing didn’t even have the ability to operate at 19.2.
The statement is correct.   The DZ doesn’t support or even make programatically the CTS/RTS lines and as you did indicate, the RI/CD didn’t generate interrupts and had to be polled.