The Cisco Catalyst 3560 Small Form-Factor Pluggable (SFP) Interconnect Cable (Part No. CAB-SFP-50CM=) provides for a low-cost, point-to-point, Gigabit Ethernet connection between Catalyst 3560 Series Switches. The 50-centimeter (cm) cable is an alternative to using SFP transceivers when interconnecting Catalyst 3560 Series Switches through their SFP ports over a short distance. All Cisco Catalyst 3560 Series Switches support the SFP Interconnect Cable.
Whena Catalyst 3560 Switch is connected to a Catalyst 3750 or any other type of Catalyst switch model, you cannot use the CAB-SFP-50CM cable. The only way to connect is to use an SFP or GBIC module.
You may connect both switches using a copper cable with SFP (GLC-T=) on both devices instead of a CAB-SFP-50CM= cable.
Note: In order to support the SFP Interconnect Cable in Catalyst 3560, you must be running Cisco IOS Software Release 12.2(25)SEA or later.