Abstract: A two piece type electrical connector is provided which is matingly connect together boards in a designated correct polarity relation. A pair of first latch members L-shaped in cross-section are projected one at each end of a mother board-side housing and each have a ridge-like friction latch. A pair of second latch members L-shaped in cross-section are projected one at each end of a daughter board-side housing. One surface side of the second latch member has a projection inserted into the guide groove. One section of the projection has a recess-like friction latch frictionally engageable with the ridge-like friction latch.

Abstract: A pair of plug-side engagement members are mounted one at each end of a plug connector attached to a mother board. A pair of receptacle-side elastic members are provided on a daughter board attached to a receptacle connector, os that the receptacle-side elastic members correspond to the plug-side engagement members. With the plug-side engagement members connected to the receptacle-side members, the former is elastically engaged to the latter so that a mechanical insertion force is exerted on the plug-side and receptacle-side connectors to force the plug and receptacle together.

Abstract: A circuit pattern layer is formed over the surface of a laminated board such that it includes one array of solder pads. The circuit pattern layer has its surface covered with a solder mask layer. The solder mask layer has a U-shaped recess at the area of the solder pad. The solder pad is exposed at the area of the U-shaped recess. Upon the soldering of the connector's connection terminal to the solder pad at the area of the U-shaped recess, a molten solder is kept in the U-shaped recess and prevented from flowing onto the adjacent connection terminal. It is thus possible to prevent a solder bridge from being created across those connection terminals.