A GOOD RS232-to-USB Adapter - for Logging

I will list here the RS232-to-USB adapters that I have
personally bought and used successfully for Logging.

-------------- What Adapter tested as GOOD? -----------------

---------------
NOTE: This item is in stock (400 available) as of 21 May, 2012

A. The "USB to RS232 Serial DB9 Cable Adapter FTDI Chipset 10 Feet"
(item RPC-USB-RS232-3M, now for about $23, as of 25 Apr 2013)
from http://www.valley-ent.com" onclick="window.open(this.href);return false; (Search for USB RS232) to get this:
http://www.valley-ent.com/catalog/rs232-serial-cable-adapter-ftdi-chipset-feet-p-530.html" onclick="window.open(this.href);return false;

There it says:
--------------------------
USB to standard 9-pin / DB9 serial port
Full Compliance with USB 1.1 and 2.0
Supports RS232 serial interface
Supports RS232 Serial DB9 devices
Supports over 1Mbps data transfer rate
Supports remote wake up and power management
Length: 10 feet
USB Chipset: FTDI

Supports: Windows 2000, Windows XP (All), Windows Server 2003, Windows Vista (All) , Windows Server 2008, Windows 7 (All), Windows Server 2008 R2, Linux and Mac OS X.

For list of drivers click on link below.
----------------------

As "USB to RS232 Serial DB9 Cable Adapter FTDI Chipset 10 Feet
Supports Windows 7 64bit", it is also available from
http://www.amazon.com" onclick="window.open(this.href);return false; and all 5 reviews are 5-star:
http://www.amazon.com/Serial-Adapter-Chipset-Supports-Windows/dp/B003N9TYW0/ref=sr_1_3?ie=UTF8&qid=1317486328&sr=8-3" onclick="window.open(this.href);return false;

It has a 10-foot cord and male attachment hardware (both convenient).

Valley Enterprises Int'l, LLC
3951 South 3300 West
Rexburg, Idaho 83440
phone: (208) 356-4785
[email protected]

b]Yes, I bought one of these from Valley Enterprises.[/b]
I tested it for Logging on three different (F1.08) SOC-Meters
with Windows Vista 32-bit, and it seems to work well.

Yes, the $25 is more expensive than many $5, $12, ... adapters, but
this one worked without even installing a driver on my Vista 32bit laptop.

----------------------
B. I just ordered (22 Oct) the Digitus DA-70156 USB 2.0 Serial Adaptor from Amazon.
It looks like it has the right specs, FTDI FT232RL chip, and the male-conection.
http://www.amazon.com/Digitus-70156-Usb-Serial-Adaptor/dp/B0030IT780" onclick="window.open(this.href);return false;
When it arrives, I will test it out.

----------------------
C. <none yet>

If other people report buyig an RS232-to-USB adapter
and using it successfully for Logging with the SOC-Meter,
I will post details (if I get them) about their "finds" here.

A. one for about $40 from Radio Shack - gascant
(It has mixed reviews at Radio Shack.)

B. one for about $30 from Mouser - ??
(Still MIGHT be having some problems, but maybe not with adapter?)

C. <none yet>

Monoprice is a good source.

http://www.monoprice.com/products/search.asp?keyword=Db9&x=0&y=0" onclick="window.open(this.href);return false;

I've always found that the Keyspan USA-19HS works very good. It has the FTDI chipset. I haven't tried it with the SOC meter though.

Almost every USB-to-RS232 adapter on the market today uses one of two chipsets:
FTDI FT232
Prolific PL2303
So from the PC side, they're almost identical. Some vendors set a custom USB VID/PID, but some don't. Of the two, I prefer the FTDI chipset because there are common tools for reprogramming the eeprom in it. I can set a custom serial number or device name, which helps in identification (especially under Linux).

One of my peeves is adapters that have no unique USB serial number! So you buy five of them, and there is no reliable way to distinguish them on the bus. At least with the FTDI-based devices, you can correct this yourself, very easily. You can also invert the signals if you have to, for custom projects.

(The Prolific chips have the advantage of doing a pretty nice 230kbps, so I'm not knocking them.)

Beyond software settings, the differences are due to the care and diligence of the people making the adapter.

Some cheap adapters drive pretty 'weak' signals, or an incorrect TTL (0 to 5v) rather than the more common -5 to +5. Ideally, you want -12 to +12 which requires a boosting line driver chip, like the MAX232. Generally, when I find that a serial device isn't working with a USB adapter, this is the root cause: not enough swing in voltage.

Some adapters take shortcuts on DTR/DSR/CSR/RI, etc.. some of the lesser-used RS-232 signals and either don't sense them or don't drive them. For devices that need special wiggling of these lines (OBD-II adapters), or worse, POWER themselves off these lines, this can be a problem. Powering from DTR is pretty common, but requires a strong line driver.

There are some non-standard adapters, like the old Xilinx and Entrega units, and the combo RS-232+Parallel adapters from years past. Avoid these.

So what to buy? Unfortunately, it requires experimentation. For the PL2303 adapters, I like the BAFO one-piece adapters. They're indestructible, and you can easily substitute a longer USB A-B cable.

Fry's has a different FTDI cable every week, so buy one, test well, then go back and get half a dozen.

The one I got from Radio Shack is the Gigaware USB-A adapter, 6' cable, Catalog # 26-949. It supports data transfer up to 128kbps. The one good thing I can say about it is that it has gold plated contacts (or maybe titanium nitride, which looks like gold). One of the reviews said to use it in the same USB port all the time. I wonder if that's my issue? Seems like I have lots to check out and report.

BTW, I wouldn't have spent that much ($40) on it but I was desperate to get something going the day that I decided to work on it. I figured it would be worth the time saved in not having to drive around to a bunch of stores to find the best one.

You were right about saving time, and even money.

However, there are mixed reviews on that adapter (as there are on most things).

When you "install" on a certain port, and later re-connect to that same port, you (usually) get the same driver and same port number assignment and port settings.

This GOOD RS232 adapter is back in stock (125 available) as of 27 Oct, 2011

I have one of these and mine works well doing Loging.

A. The "USB to RS232 Serial DB9 Cable Adapter FTDI Chipset 10 Feet"
(item RPC-USB-RS232-3M, now for $27.95 inc. shipping)
from http://www.valley-ent.com" onclick="window.open(this.href);return false; (Search for USB RS232) to get this:
http://www.valley-ent.com/catalog/rs232-serial-cable-adapter-ftdi-chipset-feet-p-530.html" onclick="window.open(this.href);return false;

This GOOD RS232 adapter is back in stock (450 available) as of 21 May 2012

I have one of these and mine works well doing Loging.

A. The "USB to RS232 Serial DB9 Cable Adapter FTDI Chipset 10 Feet"
(item RPC-USB-RS232-3M, now for $27.95 inc. shipping)
from http://www.valley-ent.com" onclick="window.open(this.href);return false; (Search for USB RS232) to get this:
http://www.valley-ent.com/catalog/rs232-serial-cable-adapter-ftdi-chipset-feet-p-530.html" onclick="window.open(this.href);return false;

Cheers, Gary

I bought generic one at FRY's a couple months ago for a different purpose. Works fine.
Is there some known issue with some of these?

Some are 0v to 5v instead of +/-12, and one gets many errors in the data stream.

So, some do not work well at higher baud rates, or with some equipment.