It is recommended that the cabling for buildings be performed by a Silicon Graphics approved vendor. Adapter cables and other required accessories can also be obtained from approved vendors. For additional information on approved vendors, contact your Silicon Graphics sales office.

FDDI media interface connectors (MICs) each contain two fiber optic lines (an input and output). MICs are constructed so that invalid connections are very difficult to make. The connector ridge or cavity (as viewed from the front of the MIC) designates the connector type and mates only with the MIC that results in a valid connection.

FDDI ST connectors each contain a single fiber optic line. Unlike MICs, ST connectors are not constructed in a manner that prevents invalid connections, you must be careful to determine that the signal direction through each connection is correct and to match the connections for primary and secondary rings.

Insertion loss, interconnection loss, and link loss are all factors that must be calculated to determine signal decibel loss within the network. Use the following tables to calculate this factor.

Table 3-1 shows typical power losses from the possible sources. These values may vary, so it is highly recommended that actual measurements be taken.

Table 3-1 shows how to make signal loss calculations. Remember, this example shows only possible loss values. To ensure accuracy, you must make actual measurements.

The margin factor in Table 3-2 is derived by subtracting the total calculated signal loss (9.5) from the maximum amount allowed (11 dB). A remainder of 1.5 dB indicates that the signal loss is safely with the limit. Table 3-3 provides data for calculating link losses.