A network interface adapted for high speed networks. The interface includes isolation circuits with a transformer containing two primary coils and two secondary coils. A wire making up each primary coil may be twisted with a wire making up a secondary. These two coils may then be co-wound on a common core. The transformer may be connected to a common mode choke. The isolation circuit may be packaged such that the transformer and coil are in a line, with isolation circuits for a plurality of pairs arranged in parallel. The interface circuit may be packaged in a connector housing, which also may be adapted for high speed performance. The housing may receive multiple isolation circuits in parallel. The housing may also include a mating contact portion in which mating contacts for signal conductors of each pair are positioned along the same side of a cavity.