Yes. The concept of half vs. full duplex only applies to bus architectures (eg Ethernet with multiple machines in a collision domain). E1s, T1s, E3/D3/OC-x,etc are not busses, and so there is no chance of multiple machines transmitting and causing a collision. This means that the transmitter does not need to wait and monitor to ensure that it is not causing a collision, and so can transmit while receiving.
Warren.
