默认自动的，先插电口，就是电口，无插光口就用光口，也可以手动切换。

命令如下：

int g0/0/24

combo-port fiber   //切换成光口

combo-port copper  //切换成电口

看当前接口用的是光口还是电口，可以通过dis int g0/0/24来查看，红色的部分就是当前用的电口：

[S5328C]dis int g0/0/24

GigabitEthernet0/0/24 current state : UP

Line protocol current state : UP

Description:route

Switch Port,PVID :   51,The Maximum Frame Length is 1600

IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 80fb-06ad-aaa1

Port Mode: FORCE COPPER

Speed :  100,  Loopback: NONE

Duplex: FULL,  Negotiation: ENABLE

Mdi   : AUTO

Last 300 seconds input rate 17102496 bits/sec, 3711 packets/sec

Last 300 seconds output rate 32314440 bits/sec, 4874 packets/sec

Input peak rate 34994152 bits/sec,Record time: 2016-03-16 20:42

Output peak rate 34489144 bits/sec,Record time: 2016-03-16 20:42

Input:  10880322831 packets, 7761767635361 bytes

Unicast        :         10880322682,Multicast          :                  18

Broadcast      :                 131,Jumbo              :                   0

CRC            :                   0,Giants             :                   0

Jabbers        :                   0,Throttles          :                   0

Runts          :                   0,DropEvents         :                   0

Alignments     :                   0,Symbols            :                   0

Ignoreds       :                   0,Frames             :                   0

Discard        :                   0,Total Error        :                   0

Output:  12908744169 packets, 10325738392975 bytes

Unicast        :         12908664331,Multicast          :               72583

Broadcast      :                7254,Jumbo              :                   1

Collisions     :                   0,Deferreds          :                   0

Late Collisions:                   0,ExcessiveCollisions:                   0

Buffers Purged :                   0

Discard        :              204905,Total Error        :                   0

Input bandwidth utilization threshold : 100.00%

Output bandwidth utilization threshold: 100.00%

Input bandwidth utilization  : 17.10%

Output bandwidth utilization : 32.31%