FIELD: telephone equipment. SUBSTANCE: method involves sending message with request to register call hold from first exchange system to second system during call, storing information about call holding in second exchange system according to request to register call for holding if it is switched to corresponding mode. Simultaneously response message is sent to register call hold. In first exchange system information about call hold registration is stored according to response message if it is switched to call hold registration mode. Then called user state is checked in call hold registration mode in second exchange system. Then message with request to process of call hold in second exchange system is entered if called user is not busy. Calling user state is checked according to request to process call hold in first exchange system and generation of call route between calling and called users in first and second exchange systems and processing calls when calling user is not busy. EFFECT: increased functional capabilities. 3 cl, 13 dwg, 4 tbl
