CH, COMM, EXP, PS, RP, SMAC
Custom communications specifications by definition are not described by any single specification. The electrical parameters will be determined by the components involved in the design. For example, if the communications utilize gigabit (GTX) transceivers in an FPGA then the electrical requirements will be prescribed by the GTX specifications.
"Internal Standards developed by Sandia National Laboratories". Experience Base, Sandia National Laboratories, Albuquerque, NM, 0000.