ADLINK USB-7250 - Manual (Page 46)

36 Operations
A relays have only NO (Normal Open) and COM (Common) con-
tacts. When the control bit is high (1), the COM terminal znd NO
pole contact. If the control bit is low (0), no contact takes place.
Current relay output status can be read back by software, and dur-
ing normal power up, reset, and power down (ejection from USB
port), the relay is low status. In addition, USB-7250 also features
programmable power-up output status, providing output state
when powered up.