warren@col.hp.com (Warren Tustin) (03/19/91)
Two things... #1. Is the 64k Video Ram upgrade as easy as just taking out the old parts and putting in 64k parts, or does something else have to be changed to affect the addressing of the RAMS? #2. FYI, I have made my own USER port to RS232 interface with one LT1133 interface IC and 4 capacitors, and of course, the connectors on both ends. It works great with a industry 1200 baud modem and most of the work is in wiring. If anyone is interested in the plans please E-mail. If enough do, I will post them. I just see the ads for $24.95 and figure I can help out anyone who can find the chip (the 1133) and is as cheap as me :^) ! P.S. This IC is specifically made to do the work of the MC1488 and 1489 and only needs 5volts and ground; it creates the needed voltages for RS232. I got mine as a sample, so I don't know what one would cost, but I would think it would be much less than $24.95. It is a 24 pin, .3" IC and I have never had any problems with this design. warren@col.hp.com