Animal ID microchips - compatibility issues, maybe non-technical? - Page 1
Forum section: electronics / general

author: AndyC_772
author_rank: Super Contributor
timestamp: June 09, 2020, 07:58:20 pm
content: Is anyone familiar with how ID chips for animals work?For years we've had a microchip reading cat flap - specificallythis one,almost.This model was originally developed and sold by Pet Porte Ltd, and that's the version we have. It works fine, but it's tired, grubby and held together with glue - so I bought a new one.The new one is sold under the "Petsafe" brand by Radio Systems Corp, whoacquired the productin 2009. Aside from some branding on the plastic parts, the new one looks identical, and even the PCB layout looks the same.But: the new unit won't scan my cats. The help page states, oddly prominently, that "Please note that chips ... starting with 977xxxxxxxxxxxx ... are not currently compatible with the cat flap" - and sure enough, that's the type of chip they have.Swap in the old PCB and it works fine.I don't believe for a moment that the cause of the incompatibility is technical, which means they must have discontinued software support for some types of chip for commercial reasons. Maybe the chip manufacturer is a competitor? Or there's a licensing issue with the protocol that they've failed to resolve?Does anyone know anything about how these chips are read out? Is there a single, standard protocol that's used? Or multiple, competing standards with patents involved, which might make multi-vendor support a legal headache?I wonder if they set the code protection bits in the MCU...?

author: Benta
author_rank: Super Contributor
timestamp: June 09, 2020, 08:28:18 pm
content: Could also just be that they've changed frequencies. RFID at 125 kHz is pretty old hat, and lots of products are moving to 13.56 MHz.

author: Fred27
author_rank: Unknown
timestamp: June 09, 2020, 10:22:26 pm
content: I think pet tags are 139kHz.If the old PCB on the new hardware works then that sounds like a good option.

author: Benta
author_rank: Super Contributor
timestamp: June 09, 2020, 11:08:33 pm
content: Quote from: Fred27 on June 09, 2020, 10:22:26 pmThat's for implanted tags. This seems to be a collar for opening a cat flap and could be anything.

author: amyk
author_rank: Super Contributor
timestamp: June 10, 2020, 12:11:45 am
content: Dive in and do some RE. Maybe you'll learn something interesting

author: DrG
author_rank: Super Contributor
timestamp: June 10, 2020, 12:46:18 am
content: Quote from: AndyC_772 on June 09, 2020, 07:58:20 pmSo, you are talking about the ID chip transmitters embedded subcutaneously in the pet, in contrast to a transmitter that can be worn on the collar - right?After a bit of reading, it is a mess. There are three frequencies that have been used, 134.2-kHz (which is also now the ISO standard ) as well as 125- and 128-kHz (I think those are older and non ISO). The chips were in use well before the ISO standard was established. When you buy a good reader (as a Vet would), it supports all three frequencies.It looks like the new flap is only going to work with the 134.2 kHz ISO.I tried to figure out the relationship between ID # and frequency to see if my thinking was on target, but it got too complicated - sometimes the first three numbers are country codes and sometimes the manufacturer codes - like I said, it is a mess. seehttps://www.pet-detect.com/pages/Interpreting-microchip-numeric-codes.aspx?pageid=610That's what it looks like to me - the cause is technical in the sense that they are not using a receiver that works with all of the transmitters (and probably not the older ones).You might have to train the cats to use a mouse

author: AndyC_772
author_rank: Super Contributor
timestamp: June 10, 2020, 05:50:29 am
content: Quote from: Benta on June 09, 2020, 11:08:33 pmThis particular flap reads the implanted chip, no collar required.Quote from: DrG on June 10, 2020, 12:46:18 amInteresting... I'll hook the boards up to a scope and see what excitation they're producing.What I find really strange is that the old, working and new, non-working PCBs look identical side by side.

author: Lamé Üsernåmê
author_rank: Newbie
timestamp: June 10, 2020, 07:07:18 am
content: "…starting with 977xxxxxxxxxxxx…" is Avid TechnologiesICAR manufacturer code. They (a) use inverted logic compared to most others, (b) use encryption (the number returned by the tag is not the registered/recorded Tag ID), and (c) have in the past been pretty heavy-handed in shutting down non-licenced commercial readers that decrypted their tags.There was quite some discussion about this years ago on Usenet's rec.pets, though most of the supporting websites have disappeared. There's also a homebrew reader & software called the "Max Microchip Project" which has some background.

author: richard.cs
author_rank: Super Contributor
timestamp: June 10, 2020, 08:52:31 am
content: Quote from: Lamé Üsernåmê on June 10, 2020, 07:07:18 amc) Sounds like the most plausible explanation for them not being supported in the new model.

author: AndyC_772
author_rank: Super Contributor
timestamp: June 10, 2020, 07:12:42 pm
content: That'll be it, thanks for the detective work.

author: aqarwaen
author_rank: Regular Contributor
timestamp: June 12, 2020, 04:34:09 pm
content: well i got here 14 year old dog and 16 year old cat here..id chip has saved serval times from animals shelter and put sleep.dead serious here about my pets age.i guess issue is non technical,since my veterinariany can read chip just fine.dog chip has worked since he was puppy.