Here are the OIDs used by Cisco 877 modems to get line speed, SNR, attenuation etc…

I mainly use this with software called PRTG

Cisco 877 SNMP OIDS (These work with the latest IOS image  (C870-ADVSECURITYK9-M), Version 12.4(22)T

. = line speed out
. = line speed in
. = output power out
. = output power in
. = attenuation down
. = attenuation up
. = SNR down
. = SNR up = CPU­ ­ . = Cisco Memory


Note: Last OID integer is the interface index number. This value can vary between routers.
To get the right interface number, use the command

show snmp mib ifmib ifindex