Hydra-CTIO GUI runs on ctioa6 and connects to the Hydra instrument through an RS-422 serial line. The ctioa6 machine is also connected to the local ethernet network allowing Hydra GUI to request status and send commands to the TCS through the GWC router.
The FOPS Guider machine is also connected to the local ethernet network allowing Hydra-CTIO to send direct commands to enable/disable guiding. The FOPS Guider machine send the guiding command thorugh an RS-232 serial line to the TCS program running on ctiox0.
The TCS program running on ctiox0 doesn't have native support for the GWC libraries so an auxiliary program running on ctiot2 provides that support. The program running on ctiot2 is called tcsrouter and basically routes messages from other applications, coming through the router, to the TCS.