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Motorola GM300 RIB cable pinout

Posted: Tue Jan 10, 2017 5:51 am
by kal
Hello Guys,
I am trying to make my own RIB cable to program my GM300 radio, i bought an after market RIB box that came with a standard RS232 cable, the other end got a DB25 male connector that i assume will connect the cable to the RJ45 that goes to the radio.
i have seen a lot of conflicting wiring schematics online, and i am getting confused, if you guys can post a picture what an actual cable should be wired like, i would appreciate that.
the pin outs that i found online got no clear explanations, would a patch of a cat5e work of so i have to get a different cable, also what resistor should i get if there is any?
thanks a lot.

Re: Motorola GM300 RIB cable pinout

Posted: Tue Jan 10, 2017 10:19 pm
by HumHead
Take a look at the batlabs.com site.

http://batlabs.com/images/maxpin.gif

You don't need a resistor. Just a jumper between pins 11 and 4 of the DB25.

Re: Motorola GM300 RIB cable pinout

Posted: Wed Jan 11, 2017 4:48 pm
by kal
thank you for your quick reply, so basically only two wires connected from the DB25 to the RJ45?
1 to 1
8 to 15
what is the function of jumping 11 and 4 on the DB25 port is they are not connected to the other end of the RJ45?

Re: Motorola GM300 RIB cable pinout

Posted: Wed Jan 11, 2017 9:21 pm
by HumHead
Since the GM / Maxreac / 1225 radios only use Ground and Bus + from programming, it connects the unused Bus - line to a bias voltage in the RIB.

It has been a while since I looked at the RIB circuit in enough detail to worry about the why.

Re: Motorola GM300 RIB cable pinout

Posted: Thu Jan 12, 2017 5:47 am
by kal
ok so i wired a cable exactly like the pinout you sent me, but no luck it says error#2 no acknowledge.

Re: Motorola GM300 RIB cable pinout

Posted: Thu Jan 12, 2017 6:26 am
by jackhackett
The pins on the modular plug are not 1 and 8.

Pin 1 on the RIB goes to pin 4 of the modular plug.
Pin 15 of the RIB goes to pin 7 of the modular plug.

This is if you use Motorola's pinout for the modular plug, they number the pins opposite from the rest of the universe (color me surprised).

In Motorola land if you hold the connector with the cable coming out the bottom and the locking tab facing away from you so that you are looking at the contacts, pin 1 is on the right.

The RIB uses a differential bus, normally it would use two signals 180 degrees out of phase, for radios that use a single ended bus one side of the RIB bus has to be connected to the bias voltage, thus the jumper.

Re: Motorola GM300 RIB cable pinout

Posted: Thu Jan 12, 2017 8:17 pm
by kal
ok so i have redone everything all over again
Pin 1 on the RIB goes to pin 4 of the modular plug.
Pin 15 of the RIB goes to pin 7 of the modular plug.
and jumped 11 and 4 on the DB25, i have made a cable with exact same pinout (pictures attached) but i still cant read the radio it still says error 2 no Acknowledge

not sure what i am still doing wrong :x

Image

Image

Image

Re: Motorola GM300 RIB cable pinout

Posted: Fri Jan 13, 2017 3:07 am
by wavetar
You have the RJ45 end backwards. Read jackhacketts post again, and look at the picture on batlabs...it says "locking tab on top" meaning facing you. You have it facing away from you. Looking at it the way you are holding it, the green should go to pin 2 and the orange to pin 5.

Re: Motorola GM300 RIB cable pinout

Posted: Fri Jan 13, 2017 4:35 am
by Bill_G
Correct.
Tab on top facing you, 1 is on the left.
Tab facing away, 1 is on the right.
Right now green is on 2 and orange is on 5.

Re: Motorola GM300 RIB cable pinout

Posted: Fri Jan 13, 2017 8:53 am
by jackhackett
It looks like you're using one of those DB25 connectors with the modular socket.

What I would have done is make a straight modular to modular jumper cable with all the wires connected using flat 8 conductor cable, then in the DB25 shell determine which two wires I needed and connect those to the pins.

That would make for a sturdier, neater looking cable and you don't have to play around with trying to get the wires into the correct slots on the modular plug. Something to consider next time... or maybe you already had it that way and had to hack the wires around?

Re: Motorola GM300 RIB cable pinout

Posted: Fri Jan 13, 2017 11:22 pm
by kal
Ok guys thank you all for your input and help, but i give up on this pinout puzzle, i am just gonna order a cable from ebay. i broke most of my pins trying to extract them and swap them around. the way i had the picture taken is to show you guys what i was doing, i understand that the locking tab should be on top, i have put the green into pin 2 and orange to pin 5 as suggested the same way i was holding the connectors, still not working, swapped the cable i made with a straight cable will all 8 pins, not a chance.
the DB25 connector is numbered 1 to 25 so no matter how i turn it around pin 1 stays pin 1 and 25 stays 25, the problem is on the RJ45 side, the colored wires got no numbers so not sure what color is what number, the connector goes only one way so not a chance to have 1 become 8 or vice versa.