This document is a user guide for AT&T hotel telephones. It describes the features and characteristics of the following products: A2100, A2210, A2220, A2310, A2410/CTM-A2411/CTM-A2411-BATT, A2420/CTM-A2421/CTM-A2421-BATT, CTM-A2510, C4000/C4001, C4010/C4011, C4100/CTM-C4101, C4200/CTM-C4201, CTM-A241P, CTM-A242P, CTM-A241HS, CTM-A242HS, CTM-A241SD and CTM-A242SD BC.