[c-nsp] 10G Xenpak 'virgin' question

[Jeff Kell]

We're trying to light up our first 10G Xenpak link, so far without
success, so I'm looking for a quick sanity check.

3750G-16TD switch with an LR Xenpak [ours], trying to link to a Ciena
[not ours] add/drop ONS.

We had some marginal power levels trying to backhaul the circuit across
campus, so we relocated the 3750 next to the fiber ingress and trying to
get the link up directly connected with no luck.

No link light (ever), not even a noise packet in the interface stats. 
The interface isn't shutdown.  I've tried it P2P (no switchport) and
trunk (switchport) and still nothing.

Is there something obvious about a 10G interface configuration that I'm
overlooking to get the thing to "speak" ? 

Jeff