My CM15A is two feet from the PC that has AHP on it. No oddball shifts or any other weird AHP problems. Every interface from the CP290 to the CM11A to the CM15A have always been connected to the PC running the control software, with never a problem. For modules the various interfaces would not reach, that's what transceivers like the TM751 and the RR501 are for. BTW if you run AHP both can be in a room. Mine are.