Problems decoding ERT SCM messages (protocol 149)

[phrrngtn]

The problem was discussed on a thread in the google group: https://groups.google.com/forum/#!msg/rtl_433/loZFvPhCxOE/BmvuBqDLAQAJ

There are two parts to this issue. One is adding support for other ERT protocols such as SCM+, IDM. This was requested in #1378. The protocols are described in the rtlamr wiki https://github.com/bemasher/rtlamr/wiki/Protocol

The other part is that it seems that rtl_433 is missing a bunch of messages that are successfully decoded by rtlamr. See below for details of the attempts to reproduce. The most promising looking diagnostics came from rtlamr when run with -samplefile. It looks like the program is saving the raw samples to a file but also indicating the sample offset, number of samples and payload of the decode. Given the fixed sample rate (2359296), the baud rate of the signal (32768), the fixed length of the packet 96 bits, it should be possible to find the samples rtlamr is framing.

rtl_tcp -a 192.168.68.126

# start the multiplexer that dups traffic on port 1234 to 7678
rtlmux -h 192.168.68.126 -p 1234

# Run the go-based s/w that successfully decodes a lot of ERT traffic
rtlamr -server=127.0.0.1:7878   -msgtype=scm,scm+,idm

# Run rtl_433 as directed but using sampling rate and frequency copied verbatim from rtlamr diagnostics
rtl_433 -d rtl_tcp://192.168.68.126:7878  -s 2359296  -f 912600155 -R 149 -S all

# 
rtl_433   -s 2359296  -r g004_912.6M_2359.3k.cu8 -W test.sr

I only saw one pulse there.

I ran rtlamr with -samplefile which saves the samples with length and offset information. I assume that it is saving the data in the same format it is getting it from rtl_tcp but I have not checked the source to verify that. phrrngtn@sdrpi:~ $ /home/pi/go/bin/rtlamr -samplefile=foo.cu8 -server=127.0.0.1:1234 -msgtype=scm,scm+,idm

16:54:11.635072 decode.go:45: CenterFreq: 912600155 16:54:11.635723 decode.go:46: SampleRate: 2359296 16:54:11.636156 decode.go:47: DataRate: 32768 16:54:11.636211 decode.go:48: ChipLength: 72 16:54:11.636256 decode.go:49: PreambleSymbols: 32 16:54:11.636302 decode.go:50: PreambleLength: 4608 16:54:11.636346 decode.go:51: PacketSymbols: 736 16:54:11.636387 decode.go:52: PacketLength: 105984 16:54:11.636443 decode.go:59: Protocols: scm+,idm,scm 16:54:11.636591 decode.go:60: Preambles: 0001011010100011,01010101010101010001011010100011,111110010101001100000 16:54:11.636731 main.go:119: GainCount: 29 {Time:2020-05-18T16:54:14.905 Offset:0 Length:229376 SCM:{ID:61105633 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66405 CRC:0x833F}} {Time:2020-05-18T16:54:15.359 Offset:229376 Length:229376 SCM:{ID:60xxxxx3 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:16.519 Offset:458752 Length:229376 SCM:{ID:60xxxxx9 Type: 4 Tamper:{Phy:00 Enc:01} Consumption: 93564 CRC:0xA02C}} {Time:2020-05-18T16:54:17.856 Offset:688128 Length:229376 SCM:{ID:61xxxxx3 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66405 CRC:0x833F}} {Time:2020-05-18T16:54:18.079 Offset:917504 Length:229376 SCM:{ID:60xxxxx3 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:20.236 Offset:1146880 Length:229376 SCM:{ID:1xxxxx22 Type:12 Tamper:{Phy:03 Enc:00} Consumption: 139242 CRC:0x9EBC}} {Time:2020-05-18T16:54:21.192 Offset:1376256 Length:229376 SCM:{ID:6xxxxx87 Type: 4 Tamper:{Phy:00 Enc:01} Consumption: 46699 CRC:0x8C1A}} {Time:2020-05-18T16:54:21.687 Offset:1605632 Length:229376 SCM:{ID:6xxxxx89 Type: 4 Tamper:{Phy:00 Enc:01} Consumption: 93564 CRC:0xA02C}} {Time:2020-05-18T16:54:24.031 Offset:1835008 Length:229376 SCM:{ID:6xxxxx87 Type: 4 Tamper:{Phy:00 Enc:01} Consumption: 46699 CRC:0x8C1A}} {Time:2020-05-18T16:54:24.195 Offset:2064384 Length:229376 SCM:{ID:6xxxxx03 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:25.526 Offset:2293760 Length:229376 SCM:{ID:6xxxxx33 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66405 CRC:0x833F}} {Time:2020-05-18T16:54:27.142 Offset:2523136 Length:229376 SCM:{ID:4xxxxx79 Type:12 Tamper:{Phy:00 Enc:00} Consumption: 629012 CRC:0xDB2C}} {Time:2020-05-18T16:54:30.082 Offset:2752512 Length:229376 SCM:{ID:6xxxxx03 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:31.633 Offset:2981888 Length:229376 SCM:{ID:6xxxxx03 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:33.030 Offset:3211264 Length:229376 SCM:{ID:6xxxxx33 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66405 CRC:0x833F}} {Time:2020-05-18T16:54:33.796 Offset:3440640 Length:229376 SCM:{ID:6xxxxx87 Type: 4 Tamper:{Phy:00 Enc:01} Consumption: 46699 CRC:0x8C1A}} {Time:2020-05-18T16:54:36.138 Offset:3670016 Length:229376 SCM:{ID:6xxxxx03 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:37.422 Offset:3899392 Length:229376 SCM:{ID:6xxxxx03 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66499 CRC:0x1D14}} {Time:2020-05-18T16:54:38.346 Offset:4128768 Length:229376 SCM:{ID:6xxxxx33 Type: 4 Tamper:{Phy:00 Enc:00} Consumption: 66405 CRC:0x833F}}

I tried to follow the instructions but pulseview would not start up by itself after this invocation. I was able to start it manually and there were samples up to the 1 second mark rtl_433 -R 149 -s 2359296 -r ~/foo.cu8 -W test.sr