I have an aeros MX-850 that was originally programmed by a dealer, but I recently got a copy of the MX-850 Editor software from a dealer (I do not, however, have a backup of my current configuration). I got a serial DB9 to 3.5mm cable, and my computer happens to have an RS232 port.

However, I can't get MX-850 Editor to connect with the remote. When I plug in the cable, the remote runs through its normal startup tests (i.e. LCD/RAM/IROUT/etc), and when I unplug the cable, it shows "FAIL! 1" on the screen. But when I try to upload or check firmware version in the MX-850 Editor software, I get error code 102-17UU-0000: "Either the com port setting is incorrect (Communications Menu) or the cable is defective."

I've tried just about everything to fix this...

• I checked the COM port is correct (it's COM1 in both MX-850 Editor's settings and in Windows Device Manager) and have tried fiddling with the numbers repeatedly.
• I have tried both my computer's built-in serial port and a USB-to-serial adapter.
• I have tried both MX-850 Editor, and NX-RM820 Editor (downloaded from this website).
• I have run Live Update.
• I've restarted the software, my computer, the remote, etc etc etc.
• I've checked that the pins should be correct for my cable (according to the store page, it's Pin 2=Tip, Pin 3=Ring, Pin 5=Shield).
• I've checked the port settings in Windows Device Manager (bits per second: 9600, data bits: 8, parity: none, stop bits: 1, flow control: none, 'use FIFO buffers' is checked)
• In the "advanced" section of the port settings in Windows Device Manager, I've tried setting the receive and transmit buffers to both the highest (14 and 16 respectively) and lowest (1 and 1) values.

The only things I haven't tried is using a different cable (I only have the one, and given that the remote reacts when I connect the cable, I'm tempted to think the cable is okay) and resetting the remote with MAIN+STOP (I don't have a backup of the current settings so I'd rather not).

Does anyone have any clue what I should try to get this working? Many thanks for reading this super long post.

This is wrong. The correct pinout for a URC serial remote is this:

[Link: remotecentral.com]

The cable you have would work on a serial Pronto remote.

Dang, I don't remember now where I read that as the pinout, but clearly it was wrong. Thanks for the tip -- I'll see if I can get it to work with a different cable.

It's right for half the remotes from that period... just not the other half. Viva la standards! :-)

I have the same problem I tried 2 different programming cables and 2 different serial to usb adapters. I have already factory reset my remote too so I am out of a remote currently.

I am not sure if my cables are correct but they are said to be for mx 850. Here are the ones I bought:

According to the "correct pinout" both of these are them...

[Link: ebay.com]

[Link: ebay.com]

I always receive "FAIL" on my LCD. Please help!

I called tech support they only told me to buy a new remote...

The 850 is a tricky remote to connect. For example on my last 3 laptops I've always had to plug in the cable to the computer (using a USB to serial adapter), then plug the cable into the remote and then start the software. If I start the software before connecting the cable it will not connect. Sometimes if I disconnect the remote to test programming, then hook the remote back up to the cable it won't connect. Then I have to restart my laptop and start the process all over again. Also what operating system are you using? Your USB adapters may not work with it. My newest laptop is windows 8 and it wouldn't connect using the adapter I had been using for my previous 2 laptops (windows 7 and vista). So I picked up an iogear guc232a installed the drivers and I have been good ever since. Also make sure the com port settings in the software match up with the com port your adapter is using. Hope this helps

Also I'm interested in knowing if anybody else has to jump through the same hoops I do to get the remote to connect.

Haven't done the 850 but have had to jump through the same hoops for other URC remotes.

I've tried all that but more importantly I even found a desktop with internal rs232 and still have the same results. Tried all different operating systems too. The remote must be dead somehow even though it works it just won't connect.

I bought another one on ebay hopefully that one will be programmable

You'd really need to use a multimeter to confirm the pinout. Note how the first poster has the wrong cable and is getting a FAIL message, and you're getting the same FAIL message...

If you're up to a little DIY, you can easily buy the parts to build a little adapter cable that swaps the ring and tip connections of a 1/8" headphone jack cable. I made one of those myself - prevents me from having to plug in entirely different cables when I swap remote types.

I don't really have any issues with my MX-850 remotes on Windows 7 and the USB-to-Serial adapter I'm using. Always works first try, regardless of connection sequence. Although I have an old MX-700 that sometimes needs the cable wiggled a bit before it'll download.

Hey, looks like some other discussions have been going on in this thread, but I built a super sketchy-looking cable with the correct pinout by cutting up two other cables and connecting the wires via a breadboard. Against all odds, it works! Thanks for pointing out the pinout screwup Daniel! :)

That series (as well as 700/800) were always a pain to connect and had high corruption rates wiping out the remote bios...sometimes you could recover the remote (not the programming), other times the remote would be toast.

We no longer support the remote for new clients and greatly recommend updating to a newer remote (many new devices can not be reliably controlled by that series of remotes either - Dish Hopper, Xfinity X1, and others)...even when using their universal browser and inputing direct hex codes.

I haven't had your problems with the 850 at all and some are controlling X1 boxes. Other than buttons wearing out after YEARS, it is one of the most reliable remotes made.

I bought a db9 to 3.5mm stero adapter cable and was having the same communication errors.

I was able to find a way to swap tip and ring on the cable and everything worked just fine.

Measure the voltage at the end of the stereo plug with the adapter connected to the computer. If the voltage (9v) is on the tip, you have the right cable, if its on the center ring, then you need to swap them. (db9 null modem would work, or kluge it like I did!)