. "heck is run every time an SFP is inserted into the 10-Port Gigabit Ethernet SPA and only SFP modules that pass this check will be usable by the 10-Port Gigabit Ethernet SPA. SFP modules exist for technologies other than Gigabit Ethernet and for products other than the 10-Port Gigabit Ethernet SPA. However, the information in this document pertains only to SFP modules that plug into the 10-Port Gig" . . .