21Slave AdderView CATxMaster AdderView CATxMaster monitorSlave monitorComputers fittedwith dual videoheadsSerialsynchronisationcableMultiple video head connectionsTwo or more AdderView CATx units can beconnected together so that they operate in asynchronised manner. Synchronised operationis useful for applications that require multiplevideo signals to be switched together. This type ofoperation is usually required where each computer isfitted with multiple video cards or video cards withmultiple video heads. Whenever a AdderView CATxchannel is switched, it sends an RS232 command outon its serial interface (marked COM1/UPGRADE on the rear panel).An AdderView CATx will switch its channel if it receives thesame command on its serial interface. Consequently, by linkingthe serial interfaces, a master unit may be made to automaticallyswitch one or more slave units as shown in the diagram.It should be noted that the synchronisation cable deliberately does not havethe transmit pin of the Slave End connector linked to the receive pin ofthe Master End connector. To do so would cause the Slave unit to be ableto switch the Master unit. This would setup an endless cyclical switchingsequence that would prevent the AdderView CATx devices from operatingcorrectly. For more details about the serial synchronisation cables, seeAppendix 7.The local user ports can alsobe used to view multiplevideo head installations.NotesIt is recommended that thesecond CAM in each pair is aUSB-type and that it is pluggedto a vacant USB port on the hostcomputer to derive its power.Pairs of CAMs can be strappedback-to-back with cable ties tocreate a tidy installation.
