Rebuilt the DEC-423 to DB-9F cable with a new db9, and it works a treat. -----Original Message----- From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of Joe Piche via cctalk Sent: Monday, November 9, 2020 10:34 PM To: 'Mark J. Blair' <n...@nf6x.net>; 'General Discussion: On-Topic and Off-Topic Posts' <cctalk@classiccmp.org> Subject: RE: VT-320 interfacing
I built that one, thank you for the link. Worked for a bit, then quit. If I move the wires around, I can get it to come and go, so it seems to be the old db9-F I used is garbage. I ordered new ones, just waiting for them to arrive. I'll send an update when I have a new connector. Thanks! -----Original Message----- From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of Mark J. Blair via cctalk Sent: Monday, November 9, 2020 7:28 PM To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org> Subject: Re: VT-320 interfacing > On Nov 9, 2020, at 5:53 PM, Grant Taylor via cctalk <cctalk@classiccmp.org> wrote: > >> The VT320 only has the DEC-423 MMJ, no RS-232. > > I /thought/ that Modified Modular Jack was simply a physical thing and completely independent of Recommended Standard 232. DECconnect (aka MMJ) interface uses RS-423 electrical signaling, but it is compatible with RS-232 signaling aside from (I think) some reduced noise immunity over long lines when not using differential receivers. The official DEC H8571 DE9 to MMJ adapter is just a plain pinout adapter which grounds the TX- and RX- signals and doesn't bother with differential signaling. It drives DSR, CTS and CD on the PC-compatible end with DSR from the MMJ interface. At the moment, one of our friends here has one for sale on his Etsy store: https://www.etsy.com/listing/875566987/dec-h8571-de9-to-mmj-terminal-serial Here's a page with details, including the wiring of that H8571 adapter: https://www.lammertbies.nl/comm/cable/dec-mmj#h71j -- Mark J. Blair, NF6X <n...@nf6x.net> https://www.nf6x.net/
