What do you mean with that? then what would be the correct type for a signed integer? Anyway, as far as I know, the NTCIP 1201 Definitions shows the object as INTEGER (0...255) they not mention anything about signed or unsigned for that object
My code accepts the type Strings of INTEGER and UNSIGNEDINTEGER. Generally the MIB should give an indication whether they are treating the data as signed or unsigned. UNSIGNEDINTEGER is not a standard type as defined by SNMP but the PDU encoding (as per the standards) does make a distinction so I added it as a type so things can get encoded properly.