I intend to use a communicator in conjunction with a burglar alarm. This is, obviously, not integral to the alarm system, otherwise an issue would not arise. The alarm manual says "It is recommended that a back EMF protection diode is used in parallel with the relay coil.". Question is, how do I determine the value of the diode? The communicator spec says the supply is "11 VDC – 14 VDC (12 VDCnominal) @ 70 mA standby, 200 mA maximum." You would think that the supplier of this device would know the answer, but they do not.