The SEII card in your computer has a single female DB-37 card-edge connector at its rear. Shown below is the schematic of this connector and the master pin-out table for it. Each signal line has its own ground reference. In the table, the pins are listed as [signal/ground]. 
 	 2/20	PHA Fast Channel
 	 3/21	PHA Live Time
 	 4/22	PHA ADC Busy
 	 5/23	PHA Pulse Reject
 	 6/24	PHA Input
 	 7/25	SEM External Enable
 	 8/26	SEM ADC-A Video Input
 	 9/27	SEM ADC-B Video Input
	10/28	SEM ADC-C Video Input
	11/29	SEM ADC-D Video Input
	12/30	SEM DAC-A [default X-Scan] Output
	13/31	SEM DAC-B [default Y-Scan] Output
	14/32	SEM Blank
	15/33	WDS Input 1
	16/34	WDS Input 2
	17/35	WDS Input 3
	18/36	WDS Input 4
	19/37	WDS Input 5