On Sat, Feb 01, 2025 at 11:01:34PM +0000, Chuck Guzis via cctalk wrote: > On 2/1/25 13:12, David Wise via cctalk wrote: [...] >> I used the 1488 and 1489 RS232 chips as level shifters on the >> semiconductor RAM board I designed for the IBM 1620. Handy. > In the 1970s/80s, there seemed to be two camps of though WRT EIA > receivers/drivers. There was the Motorola 1488/1489 crowd than there was > the TI crowd (75150/75154). Never bothered to ask which had advantages > over the other.
They're still sold and the datasheets are readily-available, so the advantages can be quickly determined: On paper, the 75150 is faster and slightly less power-thirsty than the 1488, but contains just two drivers instead of four. It also costs over twice as much. So between the two of them, the 1488 is the winner, especially if you need more than TxD and RTS. My experience with ye olde Amiga was that its 1488/1489 serial drivers got rather toasty and would occasionally go bang. I've not knowingly used the 75150, but that might just mean that it quietly gets on with its job without incident and I haven't had to desolder the crunchy remains... These days, the MAX232 (or better, one of the clones which doesn't need chunky electrolytics) is the obvious choice, even if you have +/-12V available on your board: it's cheaper and takes much the same board space as than the two-chip 1488/1489 (if five-wire serial is good enough), works off the +5V that's everywhere on your board so you save having to make space to route the +/-12V to it, and doesn't burn your finger when you touch it. Also, the number 1488 is somewhat unfortunate, especially given current events.
