The Max Plex allows you to record and playback in four channels. If you choose CIF you will be able to playback in four channels. If you select D1 you can playback 1ch at a time not 4 channels at the same time.
If your system is programmed for CIF or D1 recording only in the menu and you do not have an option to choose between the two you may try this.
Press the :
Info-Menu-PTZ-Up-Down-Enter then go to the Recording option.
Playback: 4ch playback for CIF data, 1 ch Playback for D1 Data.