Something that has frustrated me in the past is using the cumbersome method of determining the connectors required to terminate a particular optic’s fibres. We would determine the optic part code (show inventory, show module, etc) and then looked up the partcode on CCO. This was incredibly inefficient and I always felt that there had to be a way of doing this through the command line so, after many CCO documents, I found the following.

show idprom int <interface>

will show the connector type.

IOS

The following is an output from a 7600. The cards in slot 1 and 2 are LAN based (67xx) cards. The ES+ in slots 3 and 4 are Ethernet Services cards, which behaves less like a classic LAN interfaces and more like a genuine router interface, with support for CBWFQ / MQC and other features commonly found on Cisco’s software router platforms, such as a 7200.

Router#sh mod
Mod Ports Card Type                              Model              Serial No.
--- ----- -------------------------------------- ------------------ -----------
  1    8  CEF720 8 port 10GE with DFC            WS-X6708-10GE
  2   24  CEF720 24 port 1000mb SFP              WS-X6724-SFP
  3    2  7600 ES+                               7600-ES+2TG3CXL
  4    4  7600 ES+T                              76-ES+T-4TG

Some examples (filtered just to show the relevant connector lines):

Router#show idprom int tengig 1/1 | i connector
Optical connector type               :0x1 =SC
Router#show idprom int gig 2/1 | i Connector   
 Connector         : LC [0x07]
Router#show idprom int tengig 3/1 | i Connector
  Connector type                            = LC.
Router#show idprom int tengig 4/1 | i Connector
  Connector type                            = LC.

CRS

CRS is (of course) different:

RP/0/RP0/CPU0:Router#show diag 0/0/CPU0  | i Connector
Fri Jul  1 13:45:21.768 UTC
  Connector type:  SC

With these commands you’ll be able to determine what your connector types are without referring to product sheets.