Help identifying wireless doorbell signal

Get help identifying an unknown signal.
kwl3
Posts: 2
Joined: Thu Feb 22, 2018 8:54 am
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Re: Help identifying wireless doorbell signal

Post by kwl3 » Thu Aug 30, 2018 6:01 pm

After looking at the codes sent by the three of these doorbells I have physical access to, and recreating variations of their signals using a YARD Stick One (YS1), here's my stab at what these 48 bits of data might indicate:

Code: Select all

# Honeywell SERIAL ID BITS
# 0000 0000 0000 0000 1111 1111 1111 1111 2222 2222 2222 2222
# 0123 4567 89ab cdef 0123 4567 89ab cdef 0123 4567 89ab cdef
# .... .... .... .... .... .... .... .... .... .... .... ...X CHKSUM (LSB of sum of set bits in previous 23 bits)
# .... .... .... .... .... .... .... .... .... .... .... ..X. LOWBAT (1 if battery is low)
# .... .... .... .... .... .... .... .... .... .... .... .X.. IGNORED? (My receivers don't seem to care either way)
# .... .... .... .... .... .... .... .... .... .... .... X... RELAY (1 if signal is a retransmission of a received transmission, only some models)
# .... .... .... .... .... .... .... .... .... .... ...X .... SECRET KNOCK (if doorbell is pressed 3x rapidly)
# .... .... .... .... .... .... .... .... .... ..XX .... .... ALERT (00 = normal, 01 or 10 = right-left light pattern, 11 = full volume alarm)
# XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX XX.. XXX. .... KEY (any change and receiver doesn't recognize signal)
# XXXX XXXX XXXX XXXX XXXX .... .... .... .... .... .... .... KEY ID (different for each transmitter I've tested)
# .... .... .... .... .... 0000 00.0 0000 0000 00.. 000. .... KEY UNKNOWN 0 (always 0 in devices I've tested)
# .... .... .... .... .... .... ..1. .... .... .... .... .... KEY UNKNOWN 1 (always 1 in devices I've tested)
Some observations:
  • Some receiver models (like the Honeywell RDWL917AX2000/E Series 9) will immediately retransmit any valid received signal that does not already have the RELAY bit set. This seems like a useful feature to help extend the range of a signal to a more distant receiver. However the retransmission will have the RELAY bit set, so there could only be one retransmission.
  • The ALERT bits seem to indicate the receiver should take some special action. One some receivers, that action might be to blink its lights in a different pattern, or to play a siren at full volume.
The code that tos7 found on his device (FF 73 70 20 00 01) and posted above also seems to fit in with this scheme.

JF002
Posts: 1
Joined: Sun Feb 10, 2019 10:15 am

Re: Help identifying wireless doorbell signal

Post by JF002 » Sun Feb 10, 2019 10:24 am

Hi,

I hope you don't mind if I revive this old post...

I'm currently trying to send/receive the signal from the my Honeywell doorbell with an RFM69.

I've managed to successfully send the correct frame to the doorbell and make it ring (I used a RTLSDR dongle to compare the signal from the button and from my RFM69).
The information from this post and this GitHub page were priceless and allowed me to understand the signal.

Now, I'm trying to receive/decode the data frame using the RFM69 (connected to an ESP32), with no luck for now. All I receive is only noise or garbage : I should read a lot of "1 0 0" and "1 1 0", but I see a lot of longer strings of 1s and 0s.

Do you know if the RFM69 should be able to decode this data frame?
If yes, any idea on how to configure it to do so?

Thanks!

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