We propose and analyze a specific set of access rules, or ``spectrum etiquette,'' for the $59$-$64$ GHz unlicensed band to allow systems from different manufacturers with different physical and \\ medium-access control protocols to co-exist, sharing the large available bandwidth without interference. The proposed etiquette is unique in that heterogeneous systems are able to co-exist with one another, without monitoring the entire band, by means of transmissions over a common, narrow band control channel used to establish collision-free transmission schedules over the channels allocated for data transmission within the $59$-$64$ GHz band. Because no common physical layer can be assumed among different systems, the control channel is needed for the systems to schedule transmissions in the rest of the band, and the only means by which systems can communicate with one another over the control channel is the duration of each others' transmissions, which are perceived only as noise. A transmission encoding is defined based on this basic feedback to allow systems to ascertain which system can use which data channel at which time without interference. Analytical and simulation results are presented showing that the proposed etiquette is fair to all the co-existing systems, fully utilizes the spectrum, provides bounded delays for data-channel acquisition time by any given system, and provides minimum channel-use guarantees.