" You can have a maximum of 12 1000BASE-ZX GBICs per system to comply with EN55022 Class B and 24 1000BASE-ZX GBICs per system to comply with FCC Class A. "
(The previos reply mentions the ZX gbics, not CWDM).
The 4912 gigabit switch can support twelve, but it's just twelve gig ports.
Ed
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