I've had my Talker/80 for a couple of days.
My first impression is this is very nice board and the fact that it emulates multiple voice synthesizers for the Model I is amazing.
My first test was to connect it to my Model I and Expansion Interface and use the HFE image provided in the Github page. I ran all the included tests successfully. I was very impressed.
My next test was to connect the Talker/80 to the Model I directly and then connect a Quinnterface/FreHD to the Talker/80. For this the power on sequence is critical. You must power on the Talker/80 first, then the Q/F combo. I didn't wait long enough and the Talker/80 would hang. The power on sequence is mentioned in the documentation and I found that if I waited for the Talker/80 to finish with the startup message before powering on the Q/F I was able to boot. It may not be necessary to wait that long but I didn't test because it's only a matter of a couple of seconds.
My latest test was to try the Talker/80 with the MIRE and MISE. First I connected the MIRE to the Model I and then the Talker/80. I had this all on a power switch and they powered on at the same time and there wasn't an issue. I had the Talking Eliza program loaded on my MIRE emulated floppy from testing a Radio Shack Voice Synthesizer so I set the dip switches on the Talker/80 to start up in RS VS mode and reset. I then ran Talking Eliza and it worked perfectly. I then powered everything off and connected the MISE to the expansion connector on the Talker/80 and powered everything up again. Again everything came up without any issues. The Talking Eliza program still worked.
Did I mention that I am very impressed?
