1980s Echo text-to-speech synthesizer on the IMSAI 8080

video upload by df9999999999

"I recently was given a 1980s-era Echo PC voice synthesizer box with serial port interface. You simply send text to the both over the serial port and it speaks it. It uses the same chip as the old 1970s Texas Instruments speak and spell.

I figured out how to access TTY2 on the back of my newly completed IMSAI 8080 kit. Using XYBASIC, I wrote a program to speak various well known phrases from misbehaving computers featured in several scifi movies, including War Games, of course.

Accessing the TTY2 serial port on the back of the replica must be done by outputting a byte at a time to port 34. The default TTY2 baud rate was already 9600, matching that of the Echo PC. There is no handshaking. All must be coded manually. The Echo box has a very small character buffer and sends an XOFF command when the buffer fills and a XON when it clears. I check for those conditions in the BASIC program with some simple loops. Hardware handshaking on port 35 could be done, but the flag bit definitions are not well documented.

I set the cadence, pitch and inflection lower than default with a flat inflection that enhances understandability.

I also read the front panel switches to trigger the various phrases."

"Do you want to play a game?"

via Wikipedia
"The IMSAI 8080 was an early microcomputer released in late 1975, based on the Intel 8080 and later 8085 and S-100 bus.[1] It was a clone of its main competitor, the earlier MITS Altair 8800. The IMSAI is largely regarded as the first 'clone' microcomputer. The IMSAI machine ran a highly modified version of the CP/M operating system called IMDOS. It was developed, manufactured and sold by IMS Associates, Inc. (later renamed IMSAI Manufacturing Corp). In total, between 17,000 and 20,000 units were produced from 1975 to 1978."