A touch sensing apparatus for receiving input from one or more touch
stimulating devices employs a direct sequence spread spectrum (DSSS)
signaling arrangement to transmit signals from the touch stimulating
devices for identification and location determination. Active devices are
powered by an EM field and generate a touch stimulating signal that is
spread spectrum encoded for identification, and signal pickups in a
propagation layer receive the touch stimulation signals which are
identified by the DSSS encoding and located using received signal
strength (RSS) techniques. Semi-active devices are powered by an EM field
and receive code instructions to generate specific spread spectrum
signals and generate a touch-stimulating signal. Touch stimulating
devices are either tethered or tether-free, and powered by batteries or
EM fields.