Can I communicate between Hikvision intercom monitors?

Yes. In an Intercom system with 2 or more indoor stations, each station can dial or call between each other by using the following dialing format. 0- (Main indoor unit is typically 0 and other extension units are 1 thru 5) For Example: To call the Main indoor station from any indoor station you would dial 0-0 To call the first indoor extension from any indoor station, included the main indoor station, you would dial 0-1