FTDI USB TTL P1 Cable RJ12 Male Plug


FTDI FT232R USB TTL 5V to RJ11 6P6C cable is designed to facilitate communication between the Dutch Kaifa Smart Meter and a Raspberry Pi running Domoticz. It ensures the necessary signal level compatibility and utilizes the FT232R chip for reliable data transfer.


The FTDI FT232R USB TTL 5V to RJ11 6P6C cable is specifically designed for communication with the Dutch Kaifa Smart Meter and integration with Domoticz on a Raspberry Pi. Here are the key specifications and features of this cable:

Signal Level: The cable supports TTL 5V level signaling, which is compatible with the communication requirements of the Dutch Kaifa Smart Meter.

Chip: The cable incorporates the FTDI FT232R chip, which provides USB to asynchronous serial data transfer interface functionality.

Connector: The cable uses an RJ11 6P6C connector, which is commonly used for telephone connections. In this case, it is utilized for connecting to the smart meter.

Compatibility: The cable is compatible with specific smart meters, including ISKRA AM550, Kaifa MA105, Iskra ME 382, Kamstrup 162, Kamstrup 382, EN351, Landis + Gyr E350, and other models with a P1 port for smart meter communication.

Application: The cable is intended for use with Domoticz, a popular home automation platform, running on a Raspberry Pi. It enables the communication between the smart meter and the Raspberry Pi for data collection and integration into the home automation system.

The P1 port, which is the RJ-11 connection, has the serial protocol where standard IEC-62056-21 is used.

Schematische voorstelling P1 poort (ESMRv5.0 P1)

The P1 port is a 6p6c socket, commonly referred to as RJ12. The RJ11/RJ12 plug is the one we have known for years as the telephone plug. You can go with an RJ11 plug that has only the 4 middle pins connected, but your best option is to use an RJ12 connection with all 6 wires connected. That way you can optionally use the power output from the P1 port to power the reading device. The 6 pins of the P1 port are wired as shown in the table below.


1+5V           Power supply line (250mA)
2Request           Data request (high)
3Data           GNDGround for the data signal
4N.C.           Not Connected
5Data           Serial data output signal
6Power           GNDPower ground
Pin 4 is not used.

Pins 1 and 6 provide power that can be used by a connected device. According to the DSMR 5.0 standard, this output is capable of providing 250mA at 5V. This power output was not available pre-DSMR 4. But the 4. x.x standard does not give details of its maximum load, only the DSMR 5.0 standards description.

Pin 5 and 3 are serial output pins and provide a logical 1 with an output voltage of less than 1V, and a logical 0 with an output voltage of more than 4V. This is commonly referred to as TTL Serial. The Landis meter has an open collector output (pin 5), meaning that we need to add a pull-up resistor of 1-2k to allow the data output to switch between these states. Note that the output is inverted, so we’ll have to invert the signal by software or hardware. The baud rate is 115200 bps with 8 bits, no parity, and 1 stop bit (8N1). Up to DSMR 3. x the rate was only 9600 baud.


Pin 2 can be used to control the data flow from the meter. Make this pin high (>4V) to have the meter send its data on the data output pin. You can either make this permanently high, resulting in a constant flow of meter data every 10 seconds, or only when you want to request data. To stop receiving data, an OSM needs to drop the “Data Request” line – that is, set it to “high impedance”. Data transfer will stop immediately in such cases. For backward compatibility reasons, no OSM is allowed to set the “Data Request” line low (set it to GND or 0V).

The data from the P1 port is serial data, is connectable with an RJ-11 connector, and has the following signals:

1 – N/A
2 – RTS
3 – GND
4 – N/A
5 – RxD
6 – N/A

The P0 port (infra-red) is the maintenance port at the smart meter. The P1 port, using a TTL Serial protocol, provides the usage data of all connected monitoring devices (like a gas meter). The P2 port, usually wireless and communicating on 868 MHz, is used to collect data from the gas meter (which is also included in the data available on the P1 port) and is based on the M-Bus protocol. The P3 port, also wireless, communicates via GPRS (DLMS CoSEM protocol) to transmit the data from our meter to the transporter of the energy. And the P4 port is an open market interface for Independent Service Companies, grid operators, and other suppliers. We are currently only interested in the P1 port. Any system connected to P1 is designated an OSM (Other Services Module) in the DSMR standards description.

for ISKRA AM550, it needs to add one 10K resistor.
Works with Kaifa KWH smart meter. Readouts Energy +T1/+T2/-T1/-T2 and Gas connected to Synology Nas with Domoticz For
Kaifa MA105A does not need pull-up resistors.
Pinout – P1-poort – Kamstrup 162, 382 en 351
1 RTS (Request to Send)
2 GND (Ground)
3 NC (Not Connected)
4 TxD (Transmit data) Read data from the Landis E350 smart meter(add 2K pull-up resistor)

Smart Meter Description
DomotiGa support reading telegrams from Dutch Smart Meters.
A Dutch Smart Meter (using the NTA8130 standard) has a data port (also called P1) on which it dumps the data from connected utility meters every 10 seconds (DSMR 4 and older) or every 1 second (DSMR 5).
Not only electricity usage but also other connected meters (through MBus) like Gas, Heating, Cooling, and Water. Also, power generated from Sun/Wind which is delivered back to the net by the client is logged.
Requirements Smart Meter support has the following requirements: P1 (RJ11) connected via serial cable Supported DSMR Versions
The following DSMR version has been successfully validated with DomotiGa: DSMR Version Status Default Speed*
2. X Not tested 9600 7E1
2.2.X Supported 9600 7E1
3.0 Supported 9600 7E1
4.0.X Supported 115200 8N1
4.2.X Supported 115200 8N1
5.0.X Supported 115200 8N1
The Default Speed is the most commonly used serial port setting for baud rate, data bits, parity, and stop bits, but please consult your device manual first.
Some vendors use different settings. Disclaimer: Build and use this at your own risk!
The P1 port is usually present in the form of a RJ11 socket. It’s a half-duplex serial

Additional information


Landis Gyr E350, Kamstrup 162 382, Kaifa MA105A, Iskra ME 382, ISKRA AM550, Sagemcom XS210, Landis Gyr E360, Sagemcom T210-D, Sanxing SX5A2-SELS04


100cm, 180cm, 300cm, 500cm


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