Encoder receiver transmitter (ERT) is a

packet radio In digital radio, packet radio is the application of packet switching techniques to digital radio communications. Packet radio uses a packet switching Communication protocol, protocol as opposed to circuit switching or message switching protocols ...

protocol developed by

Itron The ITRON project was the first sub-project of the TRON project. It has formulated and defined Industrial TRON (ITRON) specification for an embedded real-time OS (RTOS) kernel. Originally undertaken in 1984, ITRON is a Japanese open standard for ...

for

automatic meter reading Automatic meter reading (AMR) is the technology of automatically collecting consumption, diagnostic, and status data from water meter or energy metering devices (gas, electric) and transferring that data to a central database for billing, trouble ...

. The technology is used to transmit data from utility meters over a short range so a

utility In economics, utility is a measure of a certain person's satisfaction from a certain state of the world. Over time, the term has been used with at least two meanings. * In a normative context, utility refers to a goal or objective that we wish ...

vehicle can collect meter data without a worker physically inspecting each meter. The ERT protocol was first described in . More technical detail is explained in later .

Technical details

ERT is an

OOK Ook, OoK or OOK may refer to: * Ook Chung (born 1963), Korean-Canadian writer from Quebec * On-off keying, in radio technology * Toksook Bay Airport (IATA code OOK), in Alaska * Ook!, an esoteric programming language based on Brainfuck * Ook, the ...

modulated radio signal which is transmitted in the unlicensed 900-920 MHz band. The message is transmitted in the clear and uses

Manchester encoding In telecommunications and data storage, Manchester code (also known as phase encoding, or PE) is a line code in which the encoding of each data bit is either low then high, or high then low, for equal time. It is a self-clocking signal with no ...

. The protocol uses

frequency-hopping Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter ...

, a multiple access method to avoid interference with other nearby meters. SCM and IDM packet formats are described in

SCM packet

SCM messages are 12 bytes. Each message contains single, cumulative meter reading value along with the meter serial number, commodity type and checksum and tamper flags.

IDM packet

IDM messages are 92 bytes and contain time of use consumption data. Later patents describe further variations of packets with variable length.

Implementations

Several vendors (besides Itron) have implemented ERT receivers (usually in order to read consumption data from Itron meters.) Notably, Digi sells an ERT gateway, and Grid Insight sells a PC-based product called th
AMRUSB-1
It should be possible to decode ERT signals using general purpose UHF packet radios such as th
Texas Instruments CC1101
o
Freescale MC33696
A

software-defined radio Software-defined radio (SDR) is a radio communication system where components that conventionally have been implemented in analog hardware (e.g. mixers, filters, amplifiers, modulators/ demodulators, detectors, etc.) are instead implemented ...

receiver has been implemented using inexpensive hardware
RTLAMR
and th
rtl_433
software will decode SCM messages.

Kismet (software) Kismet is a network detector, packet sniffer, and intrusion detection system for 802.11 wireless LANs. Kismet will work with any wireless card which supports raw monitoring mode, and can sniff 802.11a, 802.11b, 802.11g, and 802.11n traffic ...

has a
rtlamr data source
.

Technical details

SCM packet

IDM packet

Implementations

References

Further reading