The Tektronix 261 is a switch for 50 Ω coaxial cables with eight independent SPDT relays. Signal connections are through 24 GR-874 connectors.
Each relay has a coil that operates on 10 mA (max. 35 mA) and has a resistance of 160 Ω. There are no internal catch diodes. The relay coil contacts are brought out to the rear panel, to be controlled by a model 262 "programmer" or custom circuitry.