The old serial cables do. But the new FTDI USB cables have a standard USB end with the FTDI + Max232 chips in it and the other end is the RJ45. Here is an example.
https://www.ebay.com/itm/USB-to-RJ45-For-Cisco-USB-Console-Cable-FTDI-744664241835-Y2C9/263834776764?epid=19015691857&hash=item3d6dc734bc:g:b9cAAOSw6jJb8oOZ The do have DSR/DTR and all other signals. I've been making these for my own use and find them to be almost perfect. If I could just find one at the same price with a round black cable I would consider it 'perfect' Kurt On Wed, Jul 17, 2019, at 11:20 AM, Brian K. White wrote: > Don't the cisco cables have a rj45 on one end, and db9 on the other? > Don't you need a dupont connector for the tpdd, and a 9-25 adapter for > the M100? > And do they actually include dsr/dtr? > > Myself I am hoping to no longer use the db25 pcb. I just made a new > version just for the heck of making a more optimized version of it. I > think the most optimal is with the pcb and transistors on the tpdd end, > because it takes care of the 2x4 plug for the tpdd in a much more > convenient way than crimping and assembling a dupont connector. And the > cable and db25 comes from any generic factory molded modem cable. The > latest version I added a place to zip-tie the cable end to the pcb, and > I think that will be the final most optimal version. > > But my first samples haven't arrived yet so it's still a theory. > > It might actually be worth making a little 3d-printed housing for the > tpdd-end, to fill up that opening in the case just like the original > cable does. Not just for polarity, but also to provide strain relief, > where the case opening is what holds the cable in place instead of the > pins soldered on the pcb inside the tpdd. But that's honestly not a > major worry and I haven't actually tried to design anything. > > -- > bkw > > > On 7/17/19 1:57 PM, Kurt McCullum wrote: > > Brian, > > > > I appreciate the insights. My first reaction to seeing your new board > > was that this was a good solution. But after reading through your > > post, I changed my mind. It's probably still much easier (and cheaper) > > to buy the FTDI cable designed for CISCO routers, clip off the RJ45 > > end and then solder on the DB25. Those cables have the proper levels > > and it's easy enough to solder the DB connector. The only thing I > > don't like is the flat, light blue, cable. > > > > Kurt > > > > On Wed, Jul 17, 2019, at 10:49 AM, Brian K. White wrote: > >> Kinda sorta maybe possibly. I had thought about using one of the > >> variants of max232, instead of the 3 transistor hack. But in the end, > >> the 3 transistors is probably the cheapest and simplest circuit to make > >> a tpdd work, and this new circuit with the part that Rick Shear > >> identified, really does seem to be just like the original cable. I > >> haven't used a scope to compare the actual signals, but I have a scope > >> and an original cable so I could. I think I'll do that. > >> > >> It was a while ago so I might have some of this wrong, but what I think > >> I remember was most of those ttl to rs232 level-shifter chips don't have > >> 3 channels, and so you can't handle all 3 lines that the three > >> transistors handle, you wouldn't get DSR/DTR. And most of them also need > >> auxiliary caps for the charge pump to parasite power from the rs232 > >> lines which do not actually deliver any power to speak of. There are > >> special ones that have their own caps built in, and there are special > >> ones with more channels, or you could use multiple regular ones. So, you > >> might only be trading 3 transistors for a max232 and two caps, or a big > >> expensive special max232 etc. > >> > >> I still wouldn't mind tryng it just for the heck of it. The result would > >> be a cable that should be more technically correct, and so and more > >> reliable, when used with other random generic serial ports besides the > >> one on a model 100-200, yet still work perfectly on a model 100-200 > >> (which has pullup resistors, which the original tpdd cable circuit banks > >> on). > >> > >> But I don't think the result would be any cheaper or simpler to make. > >> > >> -- > >> bkw > >> > >> > >> On 7/17/19 10:59 AM, Kurt McCullum wrote: > >> > Brian, > >> > > >> > I noticed you have a new DB25 PCB on Osh Park. I suspect the whole > >> > TPDD cable was intended to take a TTL level floppy drive and bring it > >> > to a standard RS-232 level. I'm wondering if that same PCB could be > >> > used with one of the inexpensive TTL level FTDI USB to serial > >> > converters to create a PC to Model-T cable? The only problem I see is > >> > that the TTL level FTDI cables are all 6 wire and don't seem to have > >> > the DTR wire. But I suspect that could be hard wired some how. > >> > > >> > Kurt > >> > > >> > On Wed, Jul 10, 2019, at 11:28 PM, Brian K. White wrote: > >> >> I finally did the version of this that I had envisioned. > >> >> https://oshpark.com/shared_projects/Sk27mJwq > >> >> > >> > > >> > >> > > > >
