There is an 8-pin mini DIN connector that plugs into the TS-480, and looking at the pin chart in the owners manual, I see that pin #2 is labeled as "COM", and is the common terminal for the internal keying relay in the radio. Pin #4 is labeled as "MKE", and the chart indicates that it "connects to "COM" (pin #2) when the radio transmits". So, does anyone know if that is the way that the HLA-300 amp is keyed? By basically shorting the the two keying line conductors (using the internal relay in the radio)? Just wire up a keying line, with an RCA plug on the end that goes to the amp, and then connect the ground from the amp (on the key line) to pin #2 on the DIN plug, and the other conductor to pin #4 on the DIN plug, which goes to the radio? I am asking because I haven't wired a keying line before, and do NOT want to damage the radio or the amp. I know there is more than one method used to key an amp, in various makes and models, so I want to make sure that this is correct for this solid state amp. Thanks for any help anyone can impart.