To display hardware and diagnostic information for a networking device, a line card, a processor, a jacket card, or a chassis, use the show diag command in privileged EXEC configuration mode.
show diag [slot-number] [details | summary]
show diag [subslot slot/subslot] [details | summary]
For Null Modem config:
interface serial 0
ip address 10.1.1.1 255.255.255.0
clockrate 44732632
interface serial 1
ip address 10.1.1.2 255.255.255.0