Each V-memory location is 16 bits, or two bytes. Each character is one byte, so each register holds two characters, so your character will end up in either the high byte or the low byte of V400. You can see this if you look at V400 in a Data View and select Text as the display mode from the pull-down in the upper left. With some devices on the other end, the bytes are in reverse order within each word and you have to unravel them. Sometimes there is also an option whereby you can control the byte order from the sending device, then it's already correct by the time it hits the PLC.