An electro-mechanical lock includes a selectively operated bolt or latch which, when the bolt or latch is unblocked, may be selectively moved between a lock and an unlock position. A bolt blocking pin, which is float-mounted on a bias spring, is driven, by a first solenoid to a bolt blocking position, when the bolt is in a lock position. A spring biased solenoid pin of a second solenoid, is normally held against the blocking pin by the bias-spring and is driven by the bias-spring, to secure the bolt blocking pin in a bolt or latch locking position when the blocking pin is driven to the latch blocking position by the first solenoid. The spring biased pin is withdrawn from securing the blocking pin in bolt blocking position by energization of the second solenoid. Actuation of the solenoids to drive the bolt blocking pin into the bolt blocking position and to release the bolt blocking pin from a bolt securing position is accomplished by command or code operated switching.