An opto-electronic communication module includes a module body and a circuit board having an edge with conductive castellations extending between opposing surfaces of the circuit board. At least one opto-electronic communication device, such as an opto-electronic light source or an opto-electronic light receiver, is mounted on a surface of the circuit board in an orientation in which its optical signal communication axis is normal to the surface of the circuit board and aligned with an optical signal communication port of the module body.