我有一个 Cisco 3925，但不清楚为什么在清单中可以看到“1000BASE-SX SFP”条目。是否仅在使用 SX SFP 时可见？（我没有机会修改它。）

NAME: "CISCO3925-CHASSIS", DESCR: "CISCO3925-CHASSIS"
PID: CISCO3925-CHASSIS , VID: V02

NAME: "Cisco Services Performance Engine 100 for Cisco 3900 ISR on Slot 0", DESCR: "Cisco Services Performance Engine 100 for Cisco 3900 ISR"
PID: C3900-SPE100/K9   , VID: V01

**NAME: "1000BASE-SX SFP", DESCR: "1000BASE-SX SFP"
PID: GLC-SX-MMD        , VID: 001**

NAME: "C3900 AC Power Supply 1", DESCR: "C3900 AC Power Supply 1"
PID: PWR-3900-AC       , VID: V02

Gi0/0   << RJ45
Gi0/1   << Combo port using RJ45
Gi0/2   << Combo port using SX