An N.times.M crosspoint switch allows a signal from any one of the N
inputs to be routed to one or more of the M crosspoint switch outputs.
The switches within the crosspoint switch can be configured as voltage
mode or current mode switches. In voltage mode switching an input to the
crosspoint switch is provided to an input device, such as an amplifier,
having a low output impedance. The output of the low impedance device is
provided to a switch that connects the output of the low impedance device
to a high input impedance device, such as a band translation device. In
current mode switching, the low impedance output of the input device is
connected to selectively activated high isolation transconductance
devices having high input impedances. The outputs of the transconductance
devices are connected to low impedance devices that operate as summing
nodes.