Below There are some commands that will aide in determining what type of SFP is currently installed on your devices.
Cisco Router- example CISCO7204VXR
Show inventory raw
NAME: "module 0/1", DESCR: "1000BaseLX"
PID: , VID: , SN:
Cisco Switch- example 6500
Show inventory raw
NAME: "Chassis 1 Transceiver Te1/5/4", DESCR: "Chassis 1 X2 Transceiver 10Gbase-LX4 Te1/5/4"
PID: X2-10GB-LX4 , VID: V04 , SN: XXXXXXX
Cisco Switch- example Nexus 5K
Show interfaces capabilities
Ethernet1/2
Model: N5K-C5596UP-SUP
Type (SFP capable): 1000base-SX
Speed: 1000,10000
Duplex: full
Trunk encap. type: 802.1Q
