MR 400, MR300and MR160 are conceptually new radio modems designed for transmitting data in the VHF and UHF bands. The radio modem uses 4-state FSK modulation providing for a maximum signalling rate of 21.68 kbit/s.
The radio modem is of modular design with one to four standard RS232 ports (an RS422 or RS485 port can be used in place of two of them) available to the user. The configuration can be extended by an Ethernet interface and also by a module with analog and digital inputs/outputs. It is generally manufactured with two analog inputs and outputs and with two digital inputs and outputs.
The radio data transceiver module can be configured to a random frequency of the transmitter and receiver in the 3.2 MHz frequency range in a 25 kHz channel raster. The output and input working frequencies are mutually independent and are derived from the frequencies of four phase-hung systems programmed by the transceiver microprocessor. Channel settings are stored in the transceiver EEPROM memory and the FLASH memory module of the modem whose communication processor controls the operation of the transceiver microprocessor. The power of the radio modem transmitter is digitally set in sixteen steps from 0.1 to 5 W. In the case of high-performance radio modems of type P (see serial code) also in sixteen steps, but up to 25 W.
The design and construction of this device allows for long-term loading and for this reason it is primarily determined for continuously running applications.
Software control is compatible with the operation and configuration of the other radio modems of the MORSE system. A description of software control and configuration is available in publications describing MORSE Firmware.
The radio modem is equipment which can only be operated in the Czech Republic on the basis of Permission to operate transmitting radio stations issued by the Department of Frequency Spectrum Management at the Czech Telecommunication Office.