... GSM-R and 450MHz mode.CIR unit is made up of main rack,MMI,handset,speaker,printer,antenna ... Control unit,GPS unit,Record unit,GSM-R voice unit,GSM-R data unit,450MHz function unit, ... in and forced-release etc.(2)Control the GSM-R data unit by wireless data transfer to ... antennaAntenna color is grey,all antenna(except GPS antenna)are ellipse.Figure 10:antenna fix panel3. Electrical characteristics3.1 ...