Plip re-coding

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mat_fenwick
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Plip re-coding

Post by mat_fenwick »

Seeing as though it was fairly fresh in my mind after modifying the receiver on my new BX to accept the fob (transmitter) from the old one, I thought I would write a quick guide for future reference, now Bob Smith's site is down.

Image

This is a picture of the receiver PCB - If you look underneath the TEA550 chip you can see a row of 6 terminals on the left and 4 on the right which are either connected to the high bus (runs down the centre), the low bus (runs on the outside) or not connected to either. Depending on how these 10 pins are connected determines the 'code' of the the transmitter/receiver combination.

The transmitter has a circuit containing an identical chip, again with inputs connected or not connected, so whatever arrangement you have in the transmitter, you must have the corresponding arrangement in the receiver for it to work. The transmitter circuit has the low bus in the centre, and the high bus on the outside. It's easier to modify the receiver to the transmitter rather than the other way round - more space and it's easier to find a spare receiver should you screw it all up!

Image

Note that pins 1-10 on the transmitter correspond to 10-1 on the receiver. Also, the logic is reversed so that an input corrected to low on a transmitter should be left unconnected on the receiver and vice-versa. It may help to draw up a table like this:

The H, L, N refer to the pin connections HIGH, LOW, or NOT CONNECTED

Code: Select all

TX pin   LOGIC   LOGIC   RX pin (original configuration in brackets)
   1       H       H        1  (L)
   2       L       N        2  (L)
   3       H       H        3  (H)
   4       N       L        4  (H)
   5       N       L        5  (L)
   6       L       N        6  (H)
   7       L       N        7  (H)
   8       L       N        8  (H)
   9       H       H        9  (H)
   10      H       H        10 (H)
(This is the only way I seem to be able to insert a spaced table!)

Note how H stays as H, but N becomes L and L becomes N.

Image

You can see how I've cut the low bus connection to inputs to 1 and 2; and the high bus inputs 4, 6, 7 & 8. That's the easy bit as you can just scribe to cut the tracks.

I've then joined input 1 to the high bus, and input 4 to the low bus using just a single strand of copper wire soldered into place. It's a little bit fiddly but a lot easier than it would be with surface mount components!

EDIT - Thanks for RxBx who spotted the 'deliberate' mistake (got my right and left muddled). Shows that someone was paying attention!
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mat_fenwick
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Re: Plip re-coding

Post by mat_fenwick »

Done - sorry, some Photobucket re-organisation was to blame.
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1993 1.9 TZD Turbo Estate
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1985 Hyundai Stellar V8
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Re: Plip re-coding

Post by TizzyD »

Mat, I have a second plip that I need to recode to my current plip/receiver set up, could I just take my current plip apart and recode the second one by matching the connections on the rear ? thus making two plips work with one receiver ?
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Re: Plip re-coding

Post by mat_fenwick »

Yes, you can do that - as you already have a working one there's no need to work out the reverse logic above. Just don't do what I'd probably do and match the existing one to the non working one... :oops:
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Re: Plip re-coding

Post by TizzyD »

After much effing and blinding in the early hour of the morning I now have two plips for one receiver :D :D I gave up trying to connect each terminal to the High/Low with their own connection and ended up soldering them to other terminals which had proper connections

As you can see, terminals 2 and 3 have been soldered to terminal 1 which is Low, and 8 has been soldered to 7 which is High, I soldered terminal 10 to terminal 3 for the Low connection it needed.

Image

But I found when putting the plip back together that there is a plastic blade that runs down the middle of the terminals so I've had to re-route terminal 10 to terminal 6 and made sure that the copper wire doesn't short out terminal 9

Image

Sorry for the size of the images, I've tried shrinking them on photobucket but it's not playing ball :evil: Anyway thanks for the help Mat
'02 Clio Dynamique 1.2 16v - 92K - Sold
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Re: Plip re-coding

Post by mat_fenwick »

TizzyD wrote:But I found when putting the plip back together that there is a plastic blade that runs down the middle of the terminals so I've had to re-route terminal 10 to terminal 6 and made sure that the copper wire doesn't short out terminal 9
Yeah, sorry - that's what I meant when I said there's more space in the receiver casing - should have elaborated on that. Glad you got it working although I'd be careful with the wire running near terminal 9; maybe a dab of glue to hold it in place and insulate it?

Regarding the photos, they seem fine. I've noticed that when editing Photobucket pictures, they often seem to show up unedited when you look at the post, so assume the browser is retriveing them from a locally cached copy rather than the new image from Photobucket.
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Re: Plip re-coding

Post by TizzyD »

A bit of glue would be ideal but I don't have a glue gun so for the time being what I've done is put the plip back together and move the wire into a different position which should be ok for a while
'02 Clio Dynamique 1.2 16v - 92K - Sold
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Re: Plip re-coding

Post by Dragon Man »

i have done a little bit of testing.. if you get one of those universal remote controls for TV/VCR/air conditioning systems that has a "learn" feature...
you can actually get it to learn the code and use that to lock/unlock the car.

i have a key ring sized one and all i have done is opened it up, cut out the rubber buttons that i do not need and just left it with an unlock and lock button (which is the power and input select on the remote control) it runs off 2x coin cell batteries (same used in computers for bios).

it even works using one of those code learning watches! unlock you car from your wrist watch.. somehow that sounds 80's.. haha

just something worth having a play with :D
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always buy base spec. that way you have the fun of putting all the cool bit on your vehicle :mrgreen:
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Jaba
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Re: Plip re-coding

Post by Jaba »

Dragon Man wrote: Wed Aug 23, 2017 8:26 am i have done a little bit of testing.. if you get one of those universal remote controls for TV/VCR/air conditioning systems that has a "learn" feature...
you can actually get it to learn the code and use that to lock/unlock the car.

i have a key ring sized one and all i have done is opened it up, cut out the rubber buttons that i do not need and just left it with an unlock and lock button (which is the power and input select on the remote control) it runs off 2x coin cell batteries (same used in computers for bios).

it even works using one of those code learning watches! unlock you car from your wrist watch.. somehow that sounds 80's.. haha

just something worth having a play with :D


Respect............
The Joy of BX with just one Citroën BX to my name now. Will I sing Bye Bye to my GTI or will it be Till death us do part.
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Re: Plip re-coding

Post by Rosieuk »

Dragon Man wrote: Wed Aug 23, 2017 8:26 am i have done a little bit of testing.. if you get one of those universal remote controls for TV/VCR/air conditioning systems that has a "learn" feature...
you can actually get it to learn the code and use that to lock/unlock the car.

i have a key ring sized one and all i have done is opened it up, cut out the rubber buttons that i do not need and just left it with an unlock and lock button (which is the power and input select on the remote control) it runs off 2x coin cell batteries (same used in computers for bios).

it even works using one of those code learning watches! unlock you car from your wrist watch.. somehow that sounds 80's.. haha

just something worth having a play with :D


You can also do the same thing with the learning remote wristwatches, just put the code onto one of the buttons and you can annoy the hell out of Citroën or Renault owning relatives. Probably one of the reasons they went to the rolling code types they use now - more secure. It wouldn't have been hard to make a random code transmitter and nick away to your hearts content with the older pipe.
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