Works 100% as expected with proper code and knowledge
358187
Some reviewers have stated that these are unreliable and output bad information or that the button sends random signals. The reason they appear to be unreliable is not due to build quality but is in fact do to these reviewers using bad code to utilize the hardware. When used with the proper code the rotary ability works 100% as intended. I must admit that for someone using a rotary encoder for the first time these will appear to be poor quality, but it's simply because they operate in a very complex and unintuitive manner.

It does not help the fact that the reference materials on the Arduino website are full of false information. The sample codes they have do not work well whatsoever and should not be used in my opinion. Many people will tell you the reason these sample codes do not work well is because the encoder is bouncing so all you need to do is introduce a debounce timer in your code; this in theory could work under limited non-real-world-use conditions, but will not work well in practice, and introduces input lag which will cause the encoder to function slowly, and therefore, code debouncing timers should be avoided. Others will tell you of this problem and suggest "hardware debouncing" though the use of capacitors of various capacities soldered across the pins. This will not work because the problem is not the hardware but rather the method of interpreting it via code.

For the proper code to make this work I highly recommend using the code from the following website: [...]
BE ADVISED THERE IS ONE SMALL BUT EASILY CORRECTED ERROR IN THE CODE FOR THE FULL STEP TABLE IN VERSION 1.1

The incorrect table included in the download DO NOT USE THIS TABLE:
const unsigned char ttable[7][4] = {
  {0x0, 0x2, 0x4,  0x0}, {0x3, 0x0, 0x1, 0x10},
  {0x3, 0x2, 0x0,  0x0}, {0x3, 0x2, 0x1,  0x0},
  {0x6, 0x0, 0x4,  0x0}, {0x6, 0x5, 0x0, 0x10},
  {0x6, 0x5, 0x4,  0x0},
};

ONLY USE THIS CORRECTED TABLE:
const unsigned char ttable[7][4] = {
  {0x0, 0x2, 0x4,  0x0}, {0x3, 0x0, 0x1, 0x10},
  {0x3, 0x2, 0x0,  0x0}, {0x3, 0x2, 0x1,  0x0},
  {0x6, 0x0, 0x4,  0x0}, {0x6, 0x5, 0x0, 0x20},
  {0x6, 0x5, 0x4,  0x0},
};

As for the button sending out random signals this is because it requires a pullup resistor which is not installed on the board. Without the pullup resistor the voltage of the input the button is connected to will float and can have an unknown and fluctuating voltage which will act like random signals. This is easily corrected though: you can either enable the internal pullup resistor on the microconroller you are using (check online for how to do this with your device), or else you can implement your own pullup resistor. Either of these methods will keep the button input at a constant and known high state until pressing the button pulls the voltage low.

CONCLUSION:
When used with proper code these devices work properly and exactly as expected. I would normally remove a star for the inconvenience of there not being a pullup resistor installed for the button, but this is so easily fixed (especially if you can implement the built-in pullup resistor of your microcontroller) that it's not a big deal and doesn't warrant removing a star for an otherwise 100% functional device.
4514974
I have owned the MX-850 remote for over 5 years now.  During that time I have changed equipment many times requiring reprogramming each time.  I agree with a few of the reviews that programming can be difficult to understand, but after a bit of learning I have it working flawlessly!  Perhaps some of the reviewers lack the technical aptitude or patience to make it work.  In that case they should probably hire it done properly instead of dissing the equipment.  I have created many macros and learned commands into my remote to make it pretty much single button clicks to change most modes of operations and most entertainment sources.  It works well with the MRF-350 RF base station so that my equipment is able to be remotely installed.  The only thing visible is my 70 inch wall mounted LCD and the speakers!  My friends and family are amazed at the simplicity with which I operate my rather complex entertainment system.  If this one ever dies I will most definitely replace it with either another MX-850 or perhaps one of their newer models.
3763870
Perfect. It literally took 10 minutes to set the code and install. It works every time.  I will update this review if it starts eating batteries.
3462388
Dealer was able to program and everything worked as it should. Just a note... It does require dealer or locksmith programming.
1517577
Works exactly as expected; couldn't be happier.
2736139
Exactly what I expected and it worked fine right out of the box.
3065953
As a former  Ford mechanic from the bygone 1970's era my old code reader for my 1999 Mustang didn't work with my new 2011 Ford Ranger. I did some tinkering on the Ranger and got a "check engine" light. Well not wanting to get jammed by the Ford Dealer for a "diagnosis fee" I order this CP9185 through Amazon Prime.

It arrived intact as promised with all the attachments, Win 7 dvd,printed instructions, and a case.

Simply put a 9 volt battery in the unit, hooked it up to the access point under the steering wheel and read my code. Deleted the "reduced egr flow code" and the check engine light went out.

Problem solved in 10 minutes...........nice
4193838
I was able to program a new key without any problem.  Cable is very well built.  I have no connectivity issue.  It connects to the laptop every time.
324864
I was extremely happy with this product all around. Codes worked with no problems at all and has been useful.
2844197
It works perfectly in all modes.  No problems were encountered.
4145565
Programmed very easily and works flawlessly.
3244022
This is great if you have legacy software that requires a COM port and USB adapters do not work consistently. This fixed all the problems we were having connecting to legacy PLC's and it works every time flawlessly.
3555454
This programmer works perfectly. It doesn't have any of the issues or require any of the work-arounds of the cheaper cables. Your time is definitely worth spending a little more on a quality programmer.
3842480
Comes with a pack of anti-seize.  Plugged right in and cleared the code.
1043201
Perfect fit, good quality and brand new.

Works 100%
4955995
Simple to install.  The kit had the software and the directions were clear. Push/pull, click/click and the deed was done.  Worked perfectly from the get-go.
3417558
All the functionality of units costing much more! The U480 performed beautifully on my 1998 Volvo S70. This unit also has the ability to reset the Check Engine light, eliminating an expensive and needless trip to the mechanic. Navigation is dead simple (there are only two buttons) and the backlit screen makes use at night easy and convenient. The code reference book included is worth its weight in gold. Read the code, reference the error in the book for a description then it's off to the Internet to search for how to correct the issue in your particular vehicle. Pays for itself the first time you use it, especially if you have a smog check upcoming.