A power amplifier, PA, system (152; 156; 162) comprising: a first PA module including a plurality of first PAs configured to operate in a 2G or 3G mode, each of the plurality of first PAs being configured to amplify a radio-frequency, RF, signal for transmission; a second PA module separate from the first PA module including a plurality of second PAs configured to operate selectively in both, a 3G or 2G mode, each of the plurality of second PAs being configured to amplify an RF signal for transmission; an interface implemented as routing circuit within the first PA module , the interface configured to be capable of routing a frequency-separated RF signal received from a transceiver at a first input port of the first PA module to the one of the plurality of first PAs , the interface further configured to be capable of routing the frequency-separated RF signal to one of the plurality of second PAs and the interface including at least one single-pole double-throw switch (S1; S2; S3), the at least one single-pole double-throw switch (S1; S2; S3) having its pole connected to the first input port of the first PA module and its first throw selectively connected to the plurality of first PAs ; and a signal path implemented between the interface within the first PA module and the second PA module for routing a frequency-separated RF signal received from the transceiver at a first input port of the first PA module through the routing circuit within the first PA module to the second PA module , the second throw of the the at least one single-pole double-throw switch (S1; S2; S3) connected to an interface port (114a; 114b) of the first PA module to selectively allow the routing of the RF signal through the signal path to the plurality of second PAs . a first PA module including a plurality of first PAs configured to operate in a 2G or 3G mode, each of the plurality of first PAs being configured to amplify a radio-frequency, RF, signal for transmission; a second PA module separate from the first PA module including a plurality of second PAs configured to operate selectively in both, a 3G or 2G mode, each of the plurality of second PAs being configured to amplify an RF signal for transmission; an interface implemented as routing circuit within the first PA module , the interface configured to be capable of routing a frequency-separated RF signal received from a transceiver at a first input port of the first PA module to the one of the plurality of first PAs , the interface further configured to be capable of routing the frequency-separated RF signal to one of the plurality of second PAs and the interface including at least one single-pole double-throw switch (S1; S2; S3), the at least one single-pole double-throw switch (S1; S2; S3) having its pole connected to the first input port of the first PA module and its first throw selectively connected to the plurality of first PAs ; and a signal path implemented between the interface within the first PA module and the second PA module for routing a frequency-separated RF signal received from the transceiver at a first input port of the first PA module through the routing circuit within the first PA module to the second PA module , the second throw of the the at least one single-pole double-throw switch (S1; S2; S3) connected to an interface port (114a; 114b) of the first PA module to selectively allow the routing of the RF signal through the signal path to the plurality of second PAs . <EOS>