QCN

(Q)ualcomm (C)alibration (N)etwork file

*.QCN - original qualcomm format file, compatible with QPST (qualcomm original programm). 

Z3X SW use original format of file! this mean - you can read QCN by QPST and then write via Z3X, and QCN readed by z3x you can write via QPST. What is this QCN, what mean, not sure what mean exactly QCN word, but for each understanding you can call them: