Figure 1. Interface unit 1 Ethernet surge protector 2 Terminal strip 3 Window blower, window heater, and internal heater control 4 Window blower and internal heater switch 5 Data port 6 Window blower port 7 AC in 8 Fuses 9 Surge protectors 10 AC (mains) power switch 11 AC/DC power supply Figure 2. Measurement unit 1 Window CLW611 2 Optics unit CLO611 3 Servo drive module CLS611 4 Device control module CLC611 5 Transmitter module (including optics) CLT611 6 Interface unit (data) 7 Interface unit (control) 8 AC/DC in 9 Ventilation plug 10 Maintenance port 11 Internal heater module CLH611 12 Laser power monitor CLL611 13 Receiver module CLR611 14 Environmental sensor CLO611CB 15 Polarization unit CLP611