A communication device capable of operating in a first and a second
communications systems includes a radio signal transceiver module, a
first reception module for receiving signals from the first
communications system, a first transmitting module for transmitting
signals to the first communications system, a second reception module for
receiving signals from the second communications system, a second
transmitting module for transmitting signals to the second communications
system, a first filtering unit coupled to the first transmitting module
for filtering out signals in an overlapping frequency band between the
first transmitting module and the second reception module, and a second
filtering unit coupled to the second transmitting module for filtering
out signals in an overlapping frequency band between the second
transmitting module and the first reception module.