T-Pieces
There appear to be two types of T-piece. This is a picture of the larger type which are longer and larger than the other type, which have a much smaller black area in the middle.
T-piece is perhaps a bit of a misnomer, as they are more Y-shaped than anything.
The T-pieces are made of plastic, with two DIN sockets at one end and a single DIN socket at the other end.
The network is formed by linking together T-pieces with standard Econet DIN leads connected between the two-socket end of each T-piece. At either end of the network, a Level 1 Powered terminator can be connected, or an SJ Research Terminator Plug.