... Set Top Box: 1,RF Modulator 2,Upgrade software from PC to receiver or from receiver to receiver throught RS232 We produce ... san or letter boxUpgrade software from PC to receiver or from receiver to receiver through RS232 portThe OTA upgrade supportedMICROPROCESSORmicroprocessor:NationalChipFlash; ... input1x TV SCART(optional)1xAV4(CVBS,Audio L/R ,RF modulator output)1xRS232 (9-PIN D-sub male)(optional ...