Abstract: The operability and usage durability of a lock cancellation operating part (12e) can be improved with a simple configuration. A latch lock part (12a) and a lock cancellation operating part (12e) are integrally provided to an elastically-displaceable lock arm member (12g), which is integrally extending like a cantilever from a board connecting part (12c) solder-joined with a main wiring board. The board connecting part (12c), the latch lock part (12a), and the lock cancellation operating part (12e) are integrally provided with the lock arm member (12g) so that a retaining action and a cancelling action of the inserted signal transmission medium (F) is carried out by operation of a single member.

Abstract: To allow a quick and reliable check with a simple structure as to whether a signal transmission medium has been inserted up to a predetermined position or whether a lock operation has been completed, an insulating housing is provided with lock checking device allowing a displaced state or an engaged state of a lock member to be visually checked. With this, the displaced state of the lock member or a state in which the signal transmission medium has fallen in an engagement positioning part when the signal transmission medium is inserted up to the predetermined position can be visually checked through the lock checking device, thereby allowing the quality of an insertion state of the signal transmission medium to be immediately determined.

Abstract: The operability and usage durability of a lock cancellation operating part 12e can be improved with a simple configuration. A latch lock part 12a and a lock cancellation operating part 12e are integrally provided to an elastically-displaceable lock arm member 12g, which is integrally extending like a cantilever from a board connecting part 12c solder-joined with a main wiring board. The board connecting part 12c, the latch lock part 12a, and the lock cancellation operating part 12e are integrally provided with the lock arm member 12g so that a retaining action and a cancelling action of the inserted signal transmission medium F is carried out by operation of a single member.

Abstract: To allow a quick and reliable check with a simple structure as to whether a signal transmission medium has been inserted up to a predetermined position or whether a lock operation has been completed, an insulating housing is provided with lock checking device allowing a displaced state or an engaged state of a lock member to be visually checked. With this, the displaced state of the lock member or a state in which the signal transmission medium has fallen in an engagement positioning part when the signal transmission medium is inserted up to the predetermined position can be visually checked through the lock checking device, thereby allowing the quality of an insertion state of the signal transmission medium to be immediately determined.