3Com 3CB9RG4 Quick Start Manual page 22

22 4-Port Gigabit Ethernet Layer 3 Switching Module (GBIC) Quick Start Guide
This section describes how to install Gigabit Interface Converter (GBIC)
GBIC Transceiver
Installation transceivers in the front panel ports of the 4-port Gigabit Ethernet Layer 3
Switching Module (GBIC).
Do not install GBICs until after the 4-port Gigabit Ethernet Layer 3
Switching Module (GBIC) is installed and has powered on successfully.
(See "Verifying Module Operation" in the previous section.)
The GBIC ports on your system connect to Gigabit Ethernet networks
through a GBIC transceiver (Figure 5), which provides a high-speed
connection over fiber-optic cable. The transceiver connects to the
network using a duplex subscriber connector (SC) fiber-optic connector.
You can remove and replace the transceiver while the system is on.
Figure 5 Example of a GBIC Fiber-optic Transceiver
To ensure optimal performance, compatibility, and regulatory compliance,
use only GBIC transceivers that 3Com supports. For a list of currently
supported GBICs, see this 3Com Web site:
http://www.3com.com/gigabit_ethernet/gbics