Canon Rebel T2i Quick Start Manual page 115

Sennheiser 835 handheld microphone
This is like a wireless SM58 microphone, but it has
an omnidirectional polar pattern. It will pick up a
little more room noise than the SM58.
Position the microphone in the same manner as
the SM 58 microphone.
This microphone has a built in transmitter.
Follow the same procedure: turn on the
microphone first and then turn on the receiver
once it is plugged into the WAVE recorder and has
phantom power.
Then long press the PAIR button on the
microphone until it flashes green. Then long press
the PAIR button on the receiver until it flashes
green. A link will be established shortly and both
lights will be green.
Make sure to unmute the microphone.