device is for full duplex operation but if I connect A with Y and B with Z, is
it possible to work in half duplex ?
Yes it is possible to operate the ADM3491 in a half duplex configuration if A
is connected to Y and B is connected to Z. Figure 41 given in the ADM2582E
datasheet is a good example of where a Full Duplex RS-485 transceiver is
configured in a Half Duplex setup (figure attached)