These days you can get rs232<>TTL converter modules for less than the price of a MAX... chip; 3.3-5V (no 12V), only slightly larger than a MAX chip only; for an extra buck or so you can get it with a DE-9 connector
https://www.amazon.ca/Converter-Breakout-Computer-Electronic-Components/dp/B0B19ZCDSL/ref=asc_df_B0B19ZCDSL/?tag=googleshopc0c-20&linkCode=df0&hvadid=706760541787&hvpos=&hvnetw=g&hvrand=9876119930178959204&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000789&hvtargid=pla-2202433602635&psc=1&mcid=9cd0d7ea75903e8fa5cba0a1f9bd24a6&gad_source=1 https://www.amazon.ca/NOYITO-Module-Conversion-Arduino-communicates/dp/B07BJJC3R6/ref=asc_df_B07BJJC3R6/?tag=googleshopc0c-20&linkCode=df0&hvadid=706724917578&hvpos=&hvnetw=g&hvrand=9876119930178959204&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000789&hvtargid=pla-1678037092455&psc=1&mcid=de32eb91285c3d41b5f4851be222c963&gad_source=1 On Sun, Feb 2, 2025 at 7:41 AM Peter Corlett via cctalk < cctalk@classiccmp.org> wrote: > 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. > >
