Hi, I need another Layer 3 fast ethernet port on my 3745 router.
Can anyone pls advice if this is feasible or if there are similar solutions.
Also, what are the IOS versions and standards needed if it is compatible ?
Giuseppe is correct. HWIC is not compatible with a 3745 router. You should be looking at the NM-1FE or NM-2FE.
HWICs are supported on ISR routers 1800,2800 and 3800.
you should look for a Network Module the same that were used on C3600 series.
you can use sotware advisor tool to check what IOS is suitable for your hardware and it can provide also the exact name of the network module you are looking for.
Hope to help