For connection with a data server or a PC they are fitted with a serial connection optionally usable with either EIA-232 or EIA-485. Data transfer to the data server is using the Modbus protocol. A download of updated device software is realized through the serial connection and further on to the repeaters via radio transmission. The optional real-time clock of the devices is synchronized via the connection to the data server. The devices require a mains power supply. An assembly bracket is provided for wall or ceiling mounting of the devices, allowing the alignment of the antenna vertical to the floor for optimal reception. The device antenna may also be replaced by a displaced antenna with cord connection.