I did a little bit of re-configuring in my lab and came up with a problem with two NM cards.
Both cards are labeled as NM-4A/S on the back panels. From cisco.com, both should work in my 3620's and 2651XM's
Both cards work in the 3620, but one of them is identified as a NM-4T when I issue "sh inventory"
One of the cards works in the C2651XM but the other does not. The one that does not is identified as an NM-4T with a "sh hardware". I know that the NM-4T isn't supported in the 2600 series.
I suspect one of the NM cards is a rip off, but they do look identical and are both clearly labeled as NM-4A/S. It's not a big issue in my lab, but I was just wondering if anybody has seen this before?
NMT 4T can support 4*2Mbps link capacity to be connected but in case of 4 A/S it supports 64/128Kbps max speed link capacity.
You might want to check the data sheet and support matrix for relevant modules/interfaces with respect to the router models.
I have the same issue but with the newer HWIC cards, my problem is with a "recommended and purchased" Cisco 39xx router plus 4T module that are not working.
HWIC-4T and HWIC4A/S seems not be the same, specially with old servers..