Electrical connector system

An electrical connector system comprising:

• a receptacle connector including a receptacle housing holding a receptacle contact assembly, the receptacle housing having walls forming a receptacle, the receptacle contact assembly including receptacle signal contacts and receptacle ground contacts, the receptacle signal contacts arranged in pairs, the receptacle signal contacts arranged in receptacle signal rows, the receptacle ground contacts arranged in receptacle ground rows offset from the receptacle signal rows, wherein the receptacle signal contacts are arranged in the receptacle signal rows without any shielding structure in the receptacle signal rows between the pairs of the receptacle signal contacts;
• a plug connector configured to be plugged into the receptacle, the plug connector including a plug housing holding a plug contact assembly, the plug housing having shield walls arranged parallel to each other and shield spaces between the shield walls, the plug contact assembly including plug signal contacts arranged in pairs, the plug signal contacts located in the shield spaces in plug signal rows;
• wherein the receptacle signal contacts are mated with the corresponding plug signal contacts, and wherein the receptacle ground contacts are mated with the corresponding shield walls of the plug housing.