FMB640 RS-232 and RS-485

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RS-485 interface


RS-485 supports only half-duplex communication, which means data is transferred only one way at a time.
Note: when activated RS-485 driver chip draws a constant 30 mA current when entering Sleep or Deep sleep RS-485 will be powered off.

RS-485 modes

RS-485 receive (FMB silent) mode

RS485 Works in receive mode. Support debug and testing commands. When the command is received answer is sent after that it back up to Receive mode.

RS-485 transmit (FMB log) mode

RS-485 prints the FMB device log and does not respond to commands.

RS-485 transmit (NMEA) mode

RS-485 prints GNSS NMEA log and does not respond to commands.

RS-485 receive (LLS) mode

This mode supports up to five LLS fuel level sensors each of which has a receiver ID.

RS-485 TCP receive (ASCII/Binary) modes

In TCP ASCII/Binary mode a link with an external device using text messages can be established. Buffered modes save the information until a link with the server is established and records are sent.

RS-485 receive (TCP ASCII/Binary Buffered) mode

RS485 works in receive mode. When data received from server RS485 is switched to transmit mode. If the data server is not available, data will be saved in the buffer.

RS-232 Interface


RS-232 supports full-duplex communication which means the data can be both sent and received at the same time as they use separate transmission lines. Most of the modes are the same as for FMB640. When entering Sleep or Deep sleep RS-232 will be powered off. FMB640 RS-232 connection diagram is shown in the figure below:

FMX640 and RS232 illustration v1.2.png

RS-232 modes

Silent, Log mode, NMEA, LLS, TCP ASCII, and TCP Binary modes, TCP ASCII/Binary Buffered modes are identical to those of FMB640 RS-232 and RS-485 modes.
Note: In RS-232 LLS mode only one LLS fuel level sensor can be connected.

RS-232 LCD mode

In this mode, the user is able to communicate with the server through the terminal. A link between the FMB device and the server has to be established for this mode to function properly.


Radio-frequency identification (RFID) is the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking. FMB640 can be configured in a way to use with an RFID reader. When an RFID of some sort (typically a plastic card with a magnetic line) is used with an RFID reader that is connected to FMB640, the device creates a record with the data that the RFID reader has read and can be sent to a server with all other information. RFID ID is activated like an I/O parameter:
FMB640 RS232 RFID.png
To set up FMB640 so it can be connected to an RFID reader, some parameters have to be set up. Go to RS232 \ RS485 and set up COM1 or COM2 settings to RFID Mode or RFID MF7 Mode (the used mode depends on the mode that the RFID reader works). See Figure 922. The Baudrates for each mode are:

  • RFID Mode – 57600
  • RFID MF7 Mode – 9600

FMB640 RS232 RFIDconf.png
The difference between RFID HID Mode and RFID MF7 Mode is that in RFID MF7 Mode FMB640 understands RFID messages that are in hexadecimal text format and RFID HID Mode interprets messages that are in binary format. The type of RFID message sent to FMB640 depends on the RFID reader. For example, the RFID MF7 mode message looks like $aa$02$03$04$17$89$00$01 while the HID mode message is of the following format: "1213141519". The selected mode has to correspond to the RFID reader's mode. Please contact your local sales representative for more information about RFID IDs and devices.

REC to LCD mode

In this mode, records are sent via ports. This is an example view that is displayed in Terminal:


ATOL Tachograph mode

This mode is used to connect the ATOL tachograph.

UL202-2 Fuel Sensor

Select this mode to make Ultrasonic Fuel Sensors work on the COM port.

Satellite Backup mode

Since 00.02.05 firmware version device supports Iridium devices which can send short burst data (SBD) to the server. This means that some data can be sent from the FM device to the server through satellites. In order to get those records, you have to connect the device to FMB640 COM1 or COM2 port. Select COM1 or COM2 mode Satellite backup mode. Those settings could be found in RS232/RS485 tab in the configurator. Baudrate for satellite devices is 19200 bps. Furthermore, TSM232 functionality should be enabled. These settings can be found in the Features tab in Short burst data settings. So, with this mode, some data can be sent from the FM device to the server through satellites using Iridium devices.

RS-232 Garmin mode

Garmin provides a Fleet Management Interface Tool Kit, once FMB640 is connected to the navigator it enables the driver to have a "screen" in their vehicle for real-time navigation and messaging and offers job dispatch capabilities to help them be more efficient.
FMB640 and Garmin operational diagram is shown in the figure below:


Garmin configuration is shown in the figure below:
FMB640 RS232 Garmin.png

LLS Sensor


LLS sensor series liquid level sensors are solid-state capacitive devices with no moving parts. The sensors use capacitive technology to produce accurate liquid level measurements of standard factory-grade DIESEL OIL and PURE GASOLINE (BENZINE) carbon fuels. The LLS sensor liquid level sensors are strictly prohibited to use in any liquids which are not factory-grade carbon fuels or contain: BIOFUEL, METHANOL, ETHANOL, UREA, and similar aggressive components in pure form or as additives for factory-grade carbon fuels for use in INTERNAL COMBUSTION ENGINES. Operating media – Diesel fuel (oil), pure gasoline (benzene).
In order to use the LLS fuel counter, the newest firmware version is needed which can be obtained from Teltonika or a representative. Firmware is updated over GPRS or using a cable update method.


Parameter Value
Supply voltage +10..+50 V
Current consumption, mA (for 12/24 V) 25 mA / 50 mA
Working temperature -40..+85 ºC
Working mode Continuous
Weight < 2.0 kg
Working pressure Atmospheric

Wiring And Configuration

First of all, the LLS fuel sensor must be connected to the FMB640 device. Please find examples below:

Using RS232 socket Using RS485 socket
FMX6 ir LLS sensor pajungimo schema RS232 WIKI V1.2.png FMX6 ir LLS sensor pajungimo schema RS485 WIKI V1.0.png

Then FMB640 must be configured. Both fuel level and fuel temperature has to be set up by the configurator’s I/O menu:
FMB640 RS232 LLSmenu.png

Garmin protocols

The following is a list of protocols supported and the corresponding list of features/benefits. FMB640 can fully support Fleet Management Interface (FMI) versions up to 2.1. Other or higher versions may be supported, but Teltonika is not responsible for the changes made by Garmin, which may affect the function of FMB640 and Garmin products. For more information about Garmin products and FMI versions, please refer to Notice that some Garmin products use different connection cables than others.

Standard protocols

Text Message Protocol:

  • Allows text messages sent to the device to be displayed in "inbox" on the navigation unit;
  • Garmin can provide a confirmation that the message was read;
  • Garmin can also provide a yes/no box below the text of the message to enable a quicker response;
  • Messages can be up to 199 characters long;
  • Messages can also be generated from the device and sent to dispatcher/office;
  • Messages received will be notified to the driver through a pop-up alert on the Garmin screen;
  • Garmin provides a "virtual keyboard" for text communication.

Stop (Destination) Protocol:

  • Garmin can display a list of Stops/Jobs reported to the device in a separate category called "My Stops";
  • Driver has the ability to navigate directly to Stop from the list;
  • Garmin can provide the status of a current Stop in progress;
  • Garmin can indicate whether the driver has stopped at the location;
  • Garmin can inform how far the driver has progressed through the list of Stops;
  • Garmin can provide confirmation that the driver has received a particular Stop, familiarized himself/herself with its details, or removed it from the list;
  • Can provide confirmation that a Stop has been reached.

Estimated Time of Arrival Protocol:

  • Dispatcher/office can request the ETA of the current Stop/job in progress;
  • Garmin can notify about the actual time of arrival as well as the distance remaining to a Stop.

Auto-Arrival at Stop Protocol:

  • This feature is used to tell Garmin PND to automatically detect that it has arrived at a Stop and then to prompt the driver if he/she would like to mark the Stop as done and begin navigating to the Next Stop on the list;
  • Auto-arrival can be determined by how long the unit is stopped close to the destination (in the case driver has to park and walk) or by how close the unit needs to be to the destination before the Auto-arrival feature is activated.

Data Deletion Protocol:

  • Dispatcher/office has the ability to wipe clean the data on Garmin PND;
  • It allows to clean messages in the inbox and remove stops.

Enhanced protocols

Canned Responses/Messages:

  • Fleet managers can communicate by sending up to 200 "canned" responses from the server to be stored directly on Garmin devices;
  • Up to 50 of these canned responses can be utilized for any given scenarios;
  • Drivers can store up to 120 canned messages, eliminating the need to type while driving.

Status Protocol:

  • Up-to-the-minute communications that allow drivers to automatically send status updates;
  • Driver's units can store up to 16 status indicators such as start/stop shift, on/off the break, etc.

Supported features on TAVL client application

TAVL client application lets the user use the following features of Garmin FMI:

  • Text messaging;
  • Destination message;
  • ETA request.

Text messaging

The text messaging feature lets users communicate with the driver (the user that operates the Garmin device) by sending text messages via GPRS.

Destination message

A destination message is used to inform the driver of a new destination. When the Garmin device receives a destination message from the server it displays it as a Stop to the driver and also gives the driver the ability to start navigating to the Stop location. A new destination in TAVL client is represented as a Geozone so a new Geozone (as destination) has to be created first.

ETA request message

Estimated Time of Arrival request message is used when the user wants to know an expected arrival time to the currently active destination and the distance (in meters) from the current object location to the destination.