Transmission equipment service panel bus selecting method

A selection method of transmission equipment business board bus is used in the system with a main and a secondary business control board and a dual bus connection between the main and the secondary business control board and the business board. The method includes the following steps: (a) before each bus selection judgment, the business board judges message received by a backboard about whether relevant units of the main and the secondary control board business processing are ready and preserves the prior status after judgment; (b) in the bus selection judgment course, use the preserved prior status as the basis about whether the main and the secondary control board business processing relevant units received by the backboard bus are ready and the bus selection judgment. The invention can effectively improve the reliability of transmission equipment business board bus selection.