A METHOD, ORIGINATING OFFICE, TARGET OFFICE AND SYSTEM FOF CONTINUITY CHECK

摘要

A method for continuity check comprises: the originating office sends the call request signal carrying the predetermined called number to the target office, and at the same time the continuity check tone detection is started; the target office forwards the call request signal carrying the said predetermined called number to the originating office; the originating office carries out the circuit loop back to transfer the continuity check tone after receiving the call request signal from the target office. Accordingly, an originating office, target office and system for continuity check are also provided. The continuity check can be preformed in the case that the signal between offices does not support the continuity check in the ITU-TQ.724, ITU-TQ.783 and ITU-TQ.784 standard or that the target office does not support the continuity check.