Re: Viewdata terminal software: Any available to download?
Posted: Tue Jul 02, 2024 10:24 pm
I used to have this software (was it called QTerm?) but lost it. However I was able to reverse-engineer the code and incorporate it in my QLTerm program.stephen_usher wrote: Tue Jul 02, 2024 10:39 am Now, what I could do with is a Viewdata terminal which listens at 1200 baud but switches to 75 baud to send a character and then switches back to listen at 1200 baud. This is so as to use the analogue Miracle Systems 1200/75 QL Modem. (This is for the exhibition in November.)
I doubt that any software which came with the modem still exists.
The serial port actually transmits at 1200 baud, but the data is coded in such a way that three bytes are sent for each two bits of data. Since the serial ports transmit one start bit and two stop bits, this equivalents to 33 bits at 1200 baud which takes almost the same time as two bits at 75 bps.
So, the relationship between the two bits of data and the three bytes sent at 1200 baud is:
Code: Select all
00 00 00 00
01 FF 0F 00
10 00 F0 FF
11 FF FF FF
This is the '12P75' speed in QLTerm. Unfortunately, QVIEW doesn't support this, but using Hermes you can set the transmit and receive speed independent of each other (using the Hermes extension RXBAUD%), which is a better solution.