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I have a Nexus 5548UP and an ASA 5510 with the 4GE SSM. The 4GE has SFP ports and I would like to use them and conserve my Gigabit SFP transceivers for other uses.

The Twinax will insert into the ASA 5510, but I don't get any indication from the IOS that it is working. The interface is down and shows no transceiver.

Is Twinax compatible with plain SFP ports?

Can a 4GE SSM accept Twinax connections if the speed is set to 1000 on the switch?

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up vote 2 down vote accepted

I'm not 100 % sure, but I had the general impression that only SFP+ supports twinax. The SFP modules on a 4GE module is SFP (not SFP+).

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Thank you @pauska :) That confirms my suspicions here. Twinax is SFP+ and the port is SFP. It might work the other way around, but SFP+ certainly won't work in an SFP port. – Alain O'Dea Dec 11 '11 at 22:39

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