TO-PASS compact telecontrol modules from WAGO Corp., Germantown, WI, provide I/O monitoring, error-reporting, and supplementary I/O control via bidirectional SMS messaging. Both the TO-PASS 761-110 entry-level router and 761-216 Modbus Master use a quad-band GSM modem for basic cell service. GPRS supports packet-based data transmission. The modules each have eight 12-bit digital inputs that send 8 different error messages via email or fax. Applying voltage to the inputs enables text messages to be sent to up to 4 user-designated receivers; up to 4 outputs can be connected to the modules via SMS. User-defined text switches digital outputs on/off; TO-PASS texts a confirmation upon command execution.