An apparatus includes a first transmitter/receiver module having a housing defining a longitudinal axis and with opposed first and second longitudinal sides extending along the longitudinal axis. The housing includes a first interlocking structure disposed along the first longitudinal side and having a first power interface, a second interlocking structure disposed along the second longitudinal side and having a second power interface, and first and second signal connectors positioned at respective first and second ends of the housing. The first transmitter/receiver module is configured to assume a mated condition in stacked coupled relation with one or more additional transmitter/receiver modules through cooperative engagement of at least one of the first and second interlocking structures of the first transmitter/receiver module with corresponding complementary interlocking structure arranged on a longitudinal side of a housing of one of the additional transmitter/receiver modules.