We consider an unreliable queueing system which can be used for modeling a broadband hybrid communication channel consisting FSO (Free Space Optics) channel and radio wave channel. The radio channel is backup and is connected when the optical channel is not available. In order to save energy, a hysteresis strategy for connecting a backup channel is used. This strategy is given by two thresholds: j1 and j2,j1 ≤ j2. If the main channel fails, the backup channel connects to information transmission if the number i of customers in the system is such that i>j 2. If during backup channel operation the number of customers in the system becomes such that i ≤ j1, then the backup channel is disabled and the current customer continues to be serviced at the main server. If at some point in time the number i of customers in the system becomes such that j1