Compact electrical connector having longitudinal housing with offset guiding groove on endwall of the longitudinal housing

An electrical connector comprising:

• a longitudinal housing defining a longitudinal direction, the longitudinal housing comprising a first sidewall and a second sidewall opposite to the first sidewall, two endwalls connecting with the first and the second sidewalls, and a mating tongue and defining a receiving cavity among the first and the second sidewalls and the two endwalls and the mating tongue;
• two rows of terminals retained in the housing and arranged on opposite surfaces of the mating tongue;
• and
• a metallic shell surrounding the longitudinal housing and comprising two side plates respectively covering outer sides of the first and the second sidewalls;
• wherein
• each of the side plates defines a locking hole, at least one of the endwalls defines a guiding groove opening upwards, and a central axis in the longitudinal direction of the mating tongue is offset from a central axis in the longitudinal direction of the guiding groove;
• the guiding groove defines a first inner face proximate to the first sidewall and a second inner face opposite to the first inner face and proximate to the second sidewall, a first distance is defined between the first inner face and an inner face of the first sidewall, a second distance is defined between the second inner face and an inner face of the second sidewall, and the first distance is smaller than the second distance;
• and
• a third distance is defined between the first inner face and the second inner face, and the third distance is larger than the first distance but smaller than the second distance.