I am a bit confused on how to hookup my AM21 through a HR44. On my old HR21 the power cord on HR21 is plugged into the AM21. The 44 does not have that option since the power input is not the standard power plug. Can I simply use a standard power cord directly into the AM21. Did not want try without checking. The tech today has not seen an AM21 so he did not know. Any help would be appreciated.