Make sure that your connected to the Serial Port and not the Printer Port on the rear panel
1. Power on reset the SR620 2. Open Hyper Terminal and name your connection. Then Click OK. 3. Make sure the COM port is correct. Then Click OK. 4. Set the Bits per second: to 9600, Data bits: 8, Parity: None, Stop bits: 1, Flow control: Hardware. Click OK. 5. Go to the Properties Menu under the File Tab. 6. Click on Settings then ASCII Setup. 7. Put a check mark in the box next to Echo typed characters locally, then Click OK and then OK to exit the properties. 8. Hit the return key several times. The "ACT" light on the SR620 should turn on and off. 9. Type *idn? , Then the return key 10. Hyper Terminal should return the line "StanfordResearchSystems,SR620,0xxxx,1.48" (xxxx=the serial number of the instrument"