The hand-held transmitter SHT-12 C4D enables the remote control of up to 4 functions of a radio module or receiver of the radio series SH-12.A blue LED indicates transmission mode. It not only displays transmitted radio signals, but also provides information about the quality of radio communication and the transmitter supply voltage. The red LED indicates, depending on the wiring on the radio receiver, either the status of the receiver supply voltage or the receipt of the receiver confirmation. A confirmation of the receiver is also signaled acoustically via an integrated beeper. If the confirmation is deactivated, each change of the key status is signaled instead.With the profile seal and a special keyboard foil, the hand-held transmitter is well protected against mechanical impact and moisture and can also be used in harsh and humid environments.The hand-held transmitters of the SH-12 radio series work extremely without interference due to their special transmission characteristics.