NexRemote can pass commands through the hand control (HC) to the mount and its accessories via an auxiliary bus. During the alignment process, commands are sent by the HC (or NexRemote) to a small microcontroller that serves as an interface between the GPS module and the auxiliary bus. If the module does not respond, then the module is presumed not to be present. NexRemote would then take the time from the PC itself.
GPS receivers can also be used with Celestron mounts through a PC by use of NexGPS, which is bundled with NexRemote.