WTB: Good RS-232 to USB cables - Page 1
Forum section: electronics / general

author: Mr. Scram
author_rank: Super Contributor
timestamp: April 30, 2020, 03:37:30 pm
content: Currently I'm looking for some good quality RS-232 to USB cables to use with various pieces of equipment. I'm not interested in overly cheap options, I just want a good product at a reasonable price. I was thinking about getting some OEM FTDI-cables as they're a fairly well regarded brand, but I thought I'd as for experiences and advice before committing. What do you use and can you recommend it?

author: bd139
author_rank: Super Contributor
timestamp: April 30, 2020, 03:49:49 pm
content: Tripp-Lite ones seem to be reasonable. Not had any wonkyness from them anywayhttps://www.amazon.co.uk/dp/B00005V52C

author: Mr. Scram
author_rank: Super Contributor
timestamp: April 30, 2020, 03:59:06 pm
content: Quote from: bd139 on April 30, 2020, 03:49:49 pmI thought it looked like a wonky brand but I see they're just American.Seems to be around the same price as the FTDI ones.

author: mansaxel
author_rank: Super Contributor
timestamp: April 30, 2020, 06:09:45 pm
content: Quote from: bd139 on April 30, 2020, 03:49:49 pmI have some issues with how FTDI handles their cloners. Having said that, those (real ones) are among the best chips, and are universally supported. The Prolific ones aren't bad, but might require drivers.If you're on OS X, go FTDI. Only one supported natively. For new macs, you can get good ones with USB-C and Cisco compatible 8p8c-connector. That's my favourite at work right now.Linux or BSD? Anything goes.Windows? I don't do that.

author: rsjsouza
author_rank: Super Contributor
timestamp: April 30, 2020, 06:38:14 pm
content: One more vote forFTDI cables. They work quite well.I have a few other Prolific-based cables that work well as well, but they are ancient and sometimes finding drivers is a bit cumbersome.

author: WattsThat
author_rank: Frequent Contributor
timestamp: April 30, 2020, 06:55:20 pm
content: The overall issue that you’ll run into is that the two most commonly used parts for that functionality, the FTDI232 and MAX232 chipsets are among the most commonly counterfeited parts out there. So, a brand name is the only way to go. This is the most economical one I’ve found that works well:https://www.digikey.com/product-detail/en/ftdi/CHIPI-X10/768-1138-ND/3103022

author: Ero-Shan
author_rank: Frequent Contributor
timestamp: May 01, 2020, 05:36:23 pm
content: I used everything I could get my hands on. All of them worked well up to 19200 bps, but with 115200 they sucked big time. They were used for downloading an image to a µC, and after some seconds the download stopped with an error. Upon closer inspection, I found that at that time there was a bit of just half its wanted width.Did I say all? IthinkFTDI worked even with its virtual COM port driver (or did I already use D2XX?). So we chose FTDI for our own USB-Serial adapter. The D2XX drivers allow downloads with 1 Mbps with no problems whatsoever.You're allowed to loath them for their attempts to brick clones. But they do work very well.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 01, 2020, 06:13:59 pm
content: Quote from: Ero-Shan on May 01, 2020, 05:36:23 pmThat what I'm concluding as well. It was a stupid move though I suspect they never really grasped what they would cause. Can't really argue with the product, though.

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: May 01, 2020, 07:48:35 pm
content: Have a look at Silabs CP2102N, their driver support is also very good:https://www.silabs.com/interface/usb-bridges/usbxpresshttps://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-driversWin, Mac OS X, Linux and Android drivers. I use them for ham radio projects, especially for transceiver control (Yaesu and Icom). The only thing to keep in mind when ordering is to look for the "N" suffix, because the older CP2102 are "not recommended for new design", but still available from China as break-out boards.Rainer

author: TK
author_rank: Super Contributor
timestamp: May 01, 2020, 08:15:44 pm
content: You should clarify if you need USB-RS232 or USB-TTL cables. AFAIK FTDI does not manufacture USB-RS232 cables.I was only familiar with the FTDI to TTL cables... sorry

author: oPossum
author_rank: Super Contributor
timestamp: May 01, 2020, 08:32:13 pm
content: FTDI do make USB to RS-232. Also 422 and 485.https://www.ftdichip.com/Products/Cables/USBRS232.htmhttps://www.ftdichip.com/Products/Cables/USBRS422.htmhttps://www.ftdichip.com/Products/Cables/USBRS485.htm

author: Picuino
author_rank: Super Contributor
timestamp: May 02, 2020, 09:31:33 am
content: You should also consider installing a RS232 port directly on the PC.https://www.amazon.com/StarTech-com-Serial-Adapter-Card-PCI2S550/dp/B00006B8C0/ref=sr_1_1?dchild=1&keywords=pci+rs232&qid=1588411826&sr=8-1The USB-RS232 adapters have several problems that are not easily solved and that the RS232 PCI cards do not have

author: bd139
author_rank: Super Contributor
timestamp: May 02, 2020, 10:20:17 am
content: Much as the USB cards, those are not all made equal either. Nearly all RS232 cards don't have the correct signalling voltages which should be up to +/- 25V.Years of arguing with shitty serial cards, built in serial ports and stuff trying to program PICs with it. Ugh.

author: rsjsouza
author_rank: Super Contributor
timestamp: May 02, 2020, 10:28:18 am
content: The major caution I see with PCI cards is their driver availability, especially If you intend to use this port across OS versions or with Linux.Quote from: Ero-Shan on May 01, 2020, 05:36:23 pmYour experience is Interesting. I have used both the FTDI and the old Prolific cables with several configurations (legacy computers, embedded boards, hardware handshake) and they work very well up to 115200bps, with an edge to FTDI and their higher speeds above this mark and their broader device driver support.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 03, 2020, 07:33:12 pm
content: Quote from: TK on May 01, 2020, 08:15:44 pmIt's a good question. I'll need to check which protocol the various devices actually use.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 03, 2020, 07:34:25 pm
content: Quote from: Picuino on May 02, 2020, 09:31:33 amWhat kind of problems are we talking about?

author: Picuino
author_rank: Super Contributor
timestamp: May 03, 2020, 09:38:39 pm
content: USB connector is not robust and can be disconnected with vibration.In that case the COM port loses the connection.

author: bd139
author_rank: Super Contributor
timestamp: May 03, 2020, 10:27:09 pm
content: Hot snot fixes that. Seriously. I have actually used it to do that

author: Marck
author_rank: Regular Contributor
timestamp: May 03, 2020, 10:51:05 pm
content: We use SEALEVEL sealink+ 232-db9. Part number 2105R. We have tested many over the years with varying results. Most will work well for basic command line duties but almost all will not work when transferring config or application files. Causing corruption of the transmitted file or complete failure to transfer.The Sealink has been very successful to the point i don’t think i have had any issues in the last few years. I have to admit that i only have to resort to using a serial connection a few times a year. But before we found these ones serial transfer was always problematic.It plays well with windows 7 and 10 from my experience and i have used it on gear from two or three manufacturers and probably a total of five or six products.I still keep an old laptop that has a com port on it running XP and use that where i can. But its getting harder and harder to get newer applications to work on XP.MM

author: bateau020
author_rank: Frequent Contributor
timestamp: May 10, 2020, 09:27:57 am
content: If you have a Mac, avoid Tripp-Lite USA19HS. That one always worked for me, but it since the latest major OS update it's no longer supported natively by the OS. And when looking, none of the adapters they have are officially supported on the latest MacOS it seems.I still manage to use FTDI and Prolific chipsets though. FDTI requires an updated driver (the OS natively supports it now it seems), and one of my serial tools complains about the OS's support for Prolific. MacOS might be a bumpy ride.