10-Series Multiplex Radio Equipment (1976)
This was a multiplex radio device developed by Fujitsu Laboratories which employed gallium arsenide field-effect transistors (GaASFET) usable in microwave bands, and successfully achieved a full transition to transistors in 1976. This product series included devices with various modulation systems, transmission capacities, and relay systems over frequency bands from 400 MHz to 13 GHz.
By using microwave transistors in high-frequency amplifiers for transmission, modulation and transmission frequency conversion could be performed at low levels, increasing performance and reliability while also reducing power consumption by half. The first unit put into use was delivered to Tohoku Electric Power (Akita - Towada).