The GSM-2110 has 16 on-off inputs that can be used for monitoring alarm conditions and/or operational status of equipment. Four analog inputs can also be optionally provided, for measurement and limit detection of analog parameters. The on-off inputs can be stored and transmitted (as SMS messages) directly, or after processing with user-programmed logic functions: "AND", "OR", "EXCLUSIVE OR", and "INVERT", Up to two limit values can be set for each of the four analog inputs. Up to 20 alarm messages can be stored in GSM-2110, and the appropriate alarm and/or control messages automatically transmitted, depending on the specific conditions that have occurred. These messages can be transmitted immediately or later, to any combination of up to 4 call groups, each consisting of up to 9 phone / fax numbers or e-mail addresses which can be entered by the user and stored in the unit’s non-volatile memory.