Connections from the SEII to a 3rd party pulse processor are typically made through the external Scanning Interface Unit's DB-25 rear-panel connector labelled PHA Logic I/O. In certain circumstances, a direct connection to the DB-37 connector on the back of a SEII board is allowed. Shown below are the connections (all BNC) for the 4520 pulse processor.

SEII DB37 SIU DB25 4520 (ADC Busy) 4/22 --->> 2/15 --->> Busy In (Pulse Reject) 5/23 <<--- 3/16 <<--- no connection (Live Time) 3/21 <<--- 4/17 <<--- Busy Out (Fast Channel) 2/20 <<--- 6/19 <<--- C Rate (PHA Input) 6/24 <<--- BNC <<--- Output

Each signal line has its own ground reference (the pins are listed as signal/ground). The required connections for this pulse processor are shown to the above right.