This is the most valuable section for field troubleshooting. The Samyung SRG-150 DN Service Manual details how to enter the Test Mode (usually holding specific keys while powering on).
Symptom: The radio does not send or receive GPS position via DSC. Manual Solution: The SRG-150 DN relies on an internal GPS receiver or NMEA input. The service manual includes the NMEA 0183 pinout for the accessory port (Yellow/Green wires). It also provides the diagnostic routine to check if the internal GPS module has lost battery backup. Samyung Srg-150 Dn Service Manual
The manual opens with raw technical data: This is the most valuable section for field troubleshooting
