By: Ron  on 2016-10-24
This is a great little device! As per the retention hex nut issue, this not a deal breaker. There are some excellent mods listed in the previous reviews. Or you can get a short serial cable on eBay for less than $2. Look for: RS232 DB9 9 Pin Male to Female Serial Port Cable Industrial Adapter 1.3M. Since this cable has thumb screws on both ends, it will act as an adapter.
By: Ravenclaw123  on 2016-07-21
By: Flint Million  on 2016-04-29
It does what it says it does and does it well. The LEDs give you a very clear indication of what's going on inside your serial cable.
Only caveat is that this is designed to be a pass-through device (one side is male, one female) but both sides have the "female" retention screw holes. This means you can't plug it directly into pretty much anything, because pretty much all computer and even device serial ports also have the female screw holes. If you take the screw holes off with a hex driver, the metal shielding comes with them, so you end up with an unshielded connection. Your choice is either deal with that or get two M->F cables where both ends have the screw threads and put this in the middle. I ended up using a little Krazy Glue to glue the metal shield to the plastic casing, but without the screw holes it's probably not even doing anything anyway. Just a heads up - you may have to do a little hacking, or get extra cables with the correct ends, to get this to attach to anything.
By: jose luis ayala  on 2016-03-21
By: Stacy Unruh  on 2016-02-18
just using it for GPS signal but works great for that.
By: Mark Bitterlich  on 2016-02-06
Does exactly what I needed it to do.
By: Alexandr Kazbanov  on 2016-01-07
This small gadget saves a lot of time during installation or troubleshooting. I use it to test RS232 signal.
By: Mike Cline  on 2015-10-03
It works great! Got it fast! All is GOOD!
By: Christopher Ryan  on 2015-08-27
perfect for what i needed, good quality,
By: Steve Rohrer  on 2015-06-23
Works perfectly. Just what I needed to diagnose RS-232 issues.
By: DJR Computing Services  on 2015-06-17
Product arrived on time, as described, no complaints.
By: Jonathan  on 2015-06-11
It's not perfect. As others have mentioned, if you remove the screw captures to use it (which is necessary for most applications), the ends fall off. However, I used small counter-sunk screws (the kind you get in little baggies with every piece of Extron gear ever) to keep it together, which does the trick.
The device itself works well and is worth its weight in gold for anyone who installs a variety of rs232 controlled gear. If it were up to me, every technician I work with would carry one.
By: Michael Sablatura  on 2015-03-18
Awesome! Worth every penny.
By: Amanda Melbourne  on 2015-03-07
Works great - Very small. Neat tool for solving serial problems.
By: purple frog  on 2015-03-07
Works great - Very small. Neat tool for solving serial problems.
By: duane d ellis  on 2015-02-24
By: R Saulnier  on 2015-01-06
works as expected. one star off ... had to replace stems with 4-40s screws .. very short ... see pictures
By: Ken Andrews  on 2014-11-05
Great deal and exactly what I needed. Very satisfied.
By: RADAR  on 2014-09-07
Excellent diagnostics tool, expedites troubleshooting and repair of digital circuits. Will order additional, saved hundreds of dollars in lost time.
By: Amazon Customer  on 2014-09-03
Not much to say about this little guy other then it works. I use it to test signal between control systems (AMX, Crestron) and the devices they control. One thing I would change is to make the pegs removable. Currently if you remove them then the metal around the input and output comes off. My workaround for this is to use gender changers on both end without the pegs.
By: Stuart Bercun  on 2014-06-28
By: Stuart B  on 2014-06-28
By: AV Pro 77  on 2014-05-17
As an AV professional this is an extreme time-saver for RS232/Serial control trouble shooting. It eliminates the guess work of whether TX & RX are swapped and saves you from pulling out your multi-meter and trying to juggle test leads and DB9 cables in your hands with a flashlight. My only problem that myself and others who have reviewed this product have seen is the lug screw issue preventing you from plugging it into a piece of gear such as a TV RS232 port to determine serial TX pinout. This is easily resolved by swapping them with screws. Excellent product, will buy again!!
By: Gary Beckel  on 2014-05-09
no information to tell you what light status or color indicates, lights poorly mounted, tilt in multiple directions
was able to use it for my needs
By: Emil Marone  on 2014-01-12
Works very well and can save you lots of time connecting to serial devices for the first time. Lets you know if you need a null converter quickly
By: A D Haworth  on 2013-12-26
Small and rugged. Shows line activity for trouble shooting RS-232 data lines in the field. Met my needs for testing.
By: Bonkers Bill  on 2013-10-13
These were once hard to find - glad to have them here at Amazon. There are far too many 25 pin RS-232 testers on the market for a connector that's nearly disappeared. I have one of these in every tool kit and at every desk because they are indispensable for figuring out what's going on when a new piece of equipment wanders into the shop.
[Update December 2013]
One of the low-star reviews mentioned that these won't connect to chassis mount connectors that have jack sockets. I commented "Easy, unscrew the jack sockets on the tester". I got three new testers today and did that and the metal shells fell off. Older testers had captive metal shells so you could just unscrew the jack sockets if they get in the way. Today's don't. Four 4-40 screws will take care of it holding the shells on, but the product has changed in an unfortunate way.
By: John Berry  on 2013-10-03
People don't realize that many sensors and I/O devices still use serial connections.
These are great for testing a connection and data flow.
By: BigdoginTexas  on 2013-05-04
I like some other reviewers know for a fact that serial connectivity is not dead, finding a tester for DB-9 is not off-the shelf available for sure and finding this on Amazon was a blessing. I was in need of a test unit that was inline and simple to use and understand for checking signals from a control panel to an RS-232 external control port to mounted video projectors. I have to ascertain when a projector does not turn on or off from the wall controller if it is the wall controller / wiring, or the projector - if I call the wrong vendor responsible for warranty / repair I have to eat the service call cost. Having a small test unit with a visual indicator makes the diagnosis very simple. I did not find the LED indictors "dim" as some others have mentioned, mine were nice and bright, and exhibited no "bleed over" to the LED next to it. This unit is rugged and does what it says it will do, I did find like some other reviewers that the nuts next to one side of the connector get in the way when not mating to a cable but directly a device, simple to remove however and not a problem at all. I would recommend this to others.
By: kl  on 2013-04-13
does the deed keeps me honest in the field when setting up gear and using *customers* wires on site. (S)
By: goWolfpack  on 2013-02-18
I use this on Arduino projects to detect which lines have the data on them. I wish I had bought one of these years ago.
By: z33k  on 2013-02-08
Good for "seeing" your serial traffic and connectivity. Small and compact. Well built. LEDs light up when the pins are active and flash when traffic is passing.
By: NickyB  on 2012-09-26
Works very well, glad to have it. The female-thread retainers were cumbersome and interfered with some cables; I had to remove them with pliers. Also would have preferred lights to shine red for positive, green for negative, but it's ok this way too. Very handy item.
By: Bob S  on 2012-07-26
The light for each line shows either none (dim), green, or red. I am not sure whether green means high, and red low, or something else. It works very well for loopback tests (TX connected to RX). It can only be inserted between two cables, not between a cable and a chassis.
By: nethead  on 2012-04-14
I first used this device when I was commissioning data centers for Clearwire. Our job was to start up a newly built data center. Most network equipment is initially configured via a serial connection. Most adhere to the "Cisco standard" but some are just down right odd. One of our tasks was to connect each device to a terminal server. That meant that we had to figure out each pin-out. This little matchbox sized lamp box saved our arses. If your life involves connecting to various odd serial ports, you want this. If you have a serial cable in your kit, you want this in there with it.
By: ErnieG  on 2011-04-28
Though devices using serial connectivity are becoming a thing of the past, there are still a good number of devices that are not available with native USB connectivity and require serial port connectivity. Unfortunately, serial devices are not as plug-and-play as USB devices and thus often require some level of troubleshooting to get them up and working. This handy little link tester can be invaluable in determining if the serial connection is mated properly and if communications is occurring. I have used a number of these types of devices over the years and this particular 9-pin device is very convenient. The only drawback is the LEDs are not as bright as I would like to see. If you are in a brightly lit room or out of doors, it may be difficult to see the indication. Overall, I give this tester a thumbs-up.