Engineers now have two multifunctional transmitters at their fingertips for measuring relative humidity and temperature. The HT737 is a digital unit that measures relative humidity, temperature, dew point, and absolute humidity. It features a programmable microcontroller and RS-232 or RS-485 outputs. Digital zero and span adjustments are also possible. The HT731 is an analog unit that provides a linear 0- to 1-V dc or 0- to 10-V dc output of ambient relative humidity and temperature. It operates from 32°F to 176°F and is digitally adjustable with no potentiometers. Each probe costs $350.