In today’s world, the cellular networks are pretty good but not all networks work everywhere. The Topcon snap in RTK Cellular Module uses the GSM cellular technology. If you are using a Topcon system and GSM is not the telecommunication standard used by the provider with the best coverage in your area, it may be to your advantage to use an external modem utilizing the CDMA technology. To use an external modem with a Topcon AGI3, there are a few requirements. An RTK snap-in module is required to use RTK corrections with the AGI3. In addition, a cable will have to be added to the 40 pin connector on the AGI3 harness to allow serial communication between the serial port of the AGI3 and the external modem. When setting up the AGI3, choose “RTK (External Modem)” for the Correction System, and for the RTK Protocol choose CMR. If the external modem requires NMEA or GPS position to be input, the AGI3 can be set to output NMEA into the external modem. There are multiple options available to get your Topcon system working with the MyWay RTK network, and if you’d like to know more, contact your reseller who can provide the information needed to get you started.