F-3011-8

The F-3011-8 is an 8-channel digital military multiplex trunk system with delta modulation, made by Electromagnetica in Bucharest [1]. It was the first digital multiplex system with delta modulation made in Romania and among the first in the Warsaw Pact armies; designed by ICSITA, it was used for field trunks, to bring telephone and telegraph channels to signal centres and later as the channel unit of radio relay stations, and Electromagnetica made its zero series; its housings were die-cast [1].

It was a modular digital trunk system for C-296 heavy cable, up to 1,500 km long, or for carrying analogue telephone and data channels over radio relay [2]. Its terminal converted the eight channels with adaptive delta modulation at 51.2 kbit/s, with a quality equivalent to a 63 kbit/s PCM channel, and sent them at 480 kbit/s in HDB-3 line code; attended regenerators (F-3011-8 SRD) fed, tested and monitored up to ten unattended ones (F-3011 SRN) on each side, each covering 6 km of cable and watertight to 1 m, and there were a branching station for up to eight channels (RMF) and a portable test and talk set (EPMC) [2]. It used 19-inch racks with interchangeable boxes, integrated circuits and switched-mode supplies, with 90% integration [2].