The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port. The BIDI modules must be used in pairs. For example, if you install the GE-SFP-SX-SM1310-BIDI in the local port, you must install the GE-SFP-SX-SM1550-BIDI in the peer port.