The TotalCounterFF, TotalCounterIO and TotalCounterUSB counters are designed to be installed on opposing walls near the entrance. If the door jambs are deep enough (2.75 inches) it would be possible to install the counters on the door jambs.
If you would like to install the counters on the door frame itself, these Metal Installation Brackets can be used. These L-shaped brackets measure 1.5 by 4.5 inches on the short side and 3 x 4.5 inches on the deep side. The brackets are stainless steel and feature a hammered-black paint design.
Price is $10 per bracket, plus shipping.