Unable to establish connection between CISCO 881 and CISCO 4900M

[BennySherrin]

Currently we are attempting to connect a CISCO 881 Port 3 Ethernet port to a CISCO 4900M core switch. Everytime we connect the two devices, we are unable to achieve any link lights. If we connect any other device to these ethernet ports (Computer, Laptop, another switch), we are able to achieve a link light and establish connectivity. However everytime we connect these two, we get no link light.

Any assistance is greatly appreciated. 

[Reza Sharifi]

Are both port Gig ports? Can you try hard setting the speed on both sided of the link and test again?

HTH

[BennySherrin]

UNCLASSIFIED
No, the CISCO 881 is 10/100 and the CISCO 4900M is a Gig Port

[Joseph W. Doherty]

Are you using a cross over cable? (I don't recall whether an 881 or 4900M support auto-MDI.)