diff --git a/meson.build b/meson.build
index 76da2a56..0b0ab1dd 100644
--- a/meson.build
+++ b/meson.build
@@ -265,7 +265,7 @@ dm1801_src = src + mk22fn512_src + ['platform/targets/DM-1801/platform.c',
                                     'platform/drivers/ADC/ADC0_GDx.c',
                                     'platform/drivers/baseband/rtx_GDx.c',
                                     'platform/drivers/baseband/AT1846S.c',
-                                    'platform/drivers/baseband/HR-C6000.c',
+                                    'platform/drivers/baseband/HR_C6000.c',
                                     'platform/drivers/baseband/interfaces_GDx.c']
 
 dm1801_inc = inc + mk22fn512_inc + ['platform/targets/DM-1801']
@@ -428,7 +428,7 @@ targets = [
    'flashable': true,
    'wrap': 'UV3X0',
    'load_addr': '0x0800C000'},
-  
+
   {'name': 'mduv380g',
    'opts': mduv380g_opts,
    'flashable': true,
@@ -446,7 +446,7 @@ targets = [
    'flashable': true,
    'wrap': 'UV3X0',
    'load_addr': '0x0800C000'},
-  
+
   {'name': 'md9600',
    'opts': md9600_opts,
    'flashable': true,
diff --git a/platform/drivers/baseband/rtx_GDx.c b/platform/drivers/baseband/rtx_GDx.c
index 1587485d..e47e9688 100644
--- a/platform/drivers/baseband/rtx_GDx.c
+++ b/platform/drivers/baseband/rtx_GDx.c
@@ -18,20 +18,212 @@
  *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
  ***************************************************************************/
 
+#include <interfaces/platform.h>
+#include <interfaces/gpio.h>
+#include <interfaces/rtx.h>
+#include <calibInfo_GDx.h>
+#include <calibUtils.h>
 #include <datatypes.h>
 #include <hwconfig.h>
-#include <interfaces/platform.h>
 #include <stdbool.h>
 #include <string.h>
 #include <stdlib.h>
-#include <interfaces/rtx.h>
-#include <stdio.h>
+#include "HR_C6000.h"
+#include "AT1846S.h"
 
 OS_MUTEX *cfgMutex;               /* Mutex for incoming config messages */
 OS_Q cfgMailbox;                  /* Queue for incoming config messages */
 
+const gdxCalibration_t *calData;  /* Pointer to calibration data        */
+
 rtxStatus_t rtxStatus;            /* RTX driver status                  */
 
+/*
+ * Helper functions to reduce code mess. They all access 'rtxStatus'
+ * internally.
+ */
+
+int8_t _getBandFromFrequency(freq_t freq)
+{
+    if((freq >= FREQ_LIMIT_VHF_LO) && (freq <= FREQ_LIMIT_VHF_HI)) return 0;
+    if((freq >= FREQ_LIMIT_UHF_LO) && (freq <= FREQ_LIMIT_UHF_HI)) return 1;
+    return -1;
+}
+
+void _setBandwidth()
+{
+    /* Override bandwidth configuration for digital modes */
+    uint8_t bandwidth = BW_12_5;
+    if(rtxStatus.opMode == FM) bandwidth = rtxStatus.bandwidth;
+
+    switch(bandwidth)
+    {
+        case BW_12_5:
+            AT1846S_setBandwidth(AT1846S_BW_12P5);
+            break;
+
+        case BW_20:
+        case BW_25:
+            AT1846S_setBandwidth(AT1846S_BW_25);
+            break;
+
+        default:
+            break;
+    }
+}
+
+void _setOpMode()
+{
+    switch(rtxStatus.opMode)
+    {
+        case FM:
+            gpio_setPin(RX_AUDIO_MUX);          /* Audio out to amplifier */
+            gpio_clearPin(TX_AUDIO_MUX);        /* Audio in to microphone */
+            AT1846S_setOpMode(AT1846S_OP_FM);
+            break;
+
+        case DMR:
+            gpio_clearPin(RX_AUDIO_MUX);        /* Audio out to HR_C6000  */
+            gpio_setPin(TX_AUDIO_MUX);          /* Audio in from HR_C6000 */
+            AT1846S_setOpMode(AT1846S_OP_FM);
+            break;
+
+        default:
+            break;
+    }
+}
+
+void _setVcoFrequency()
+{
+    freq_t freq = rtxStatus.rxFrequency;
+    if(rtxStatus.opStatus == TX) freq = rtxStatus.txFrequency;
+    AT1846S_setFrequency(freq);
+}
+
+void _enableTxStage()
+{
+    if(rtxStatus.txDisable == 1) return;
+
+    gpio_clearPin(VHF_LNA_EN);
+    gpio_clearPin(UHF_LNA_EN);
+    gpio_clearPin(VHF_PA_EN);
+    gpio_clearPin(UHF_PA_EN);
+
+    int8_t band = _getBandFromFrequency(rtxStatus.txFrequency);
+    if(band < 0) return;
+
+    /*
+     * Set transmit power. Initial setting is 1W, overridden to 5W if tx power
+     * is greater than 1W.
+     * TODO: increase granularity
+     */
+//     const uint8_t *paramPtr = calData->txLowPower;
+//     if(rtxStatus.txPower > 1.0f) paramPtr = calData->txHighPower;
+//     uint8_t apc = interpCalParameter(rtxStatus.txFrequency, calData->txFreq,
+//                                      paramPtr, 9);
+//     DAC->DHR12L1 = apc * 0xFF;
+
+    if(band == 0)
+    {
+        gpio_setPin(VHF_PA_EN);
+    }
+    else
+    {
+        gpio_setPin(UHF_PA_EN);
+    }
+
+    rtxStatus.opStatus = TX;
+    _setVcoFrequency();
+    AT1846S_setFuncMode(AT1846S_TX);
+}
+
+void _enableRxStage()
+{
+    gpio_clearPin(VHF_LNA_EN);
+    gpio_clearPin(UHF_LNA_EN);
+    gpio_clearPin(VHF_PA_EN);
+    gpio_clearPin(UHF_PA_EN);
+
+    int8_t band = _getBandFromFrequency(rtxStatus.rxFrequency);
+    if(band < 0) return;
+
+    if(band == 0)
+    {
+        gpio_setPin(VHF_LNA_EN);
+    }
+    else
+    {
+        gpio_setPin(UHF_LNA_EN);
+    }
+
+    rtxStatus.opStatus = RX;
+    _setVcoFrequency();
+    AT1846S_setFuncMode(AT1846S_RX);
+}
+
+void _disableRtxStages()
+{
+    gpio_clearPin(VHF_LNA_EN);
+    gpio_clearPin(UHF_LNA_EN);
+    gpio_clearPin(VHF_PA_EN);
+    gpio_clearPin(UHF_PA_EN);
+    AT1846S_setFuncMode(AT1846S_OFF);
+    rtxStatus.opStatus = OFF;
+}
+
+void _updateTuningParams()
+{
+    int8_t band = _getBandFromFrequency(rtxStatus.rxFrequency);
+    if(band < 0) return;
+
+    const bandCalData_t *cal = &(calData->data[band]);
+
+    AT1846S_setPgaGain(cal->PGA_gain);
+    AT1846S_setMicGain(cal->analogMicGain);
+    AT1846S_setTxDeviation(cal->txDev_tone);
+    AT1846S_setAgcGain(cal->rxAGCgain);
+    AT1846S_setRxAudioGain(cal->rxAudioGainWideband, cal->rxAudioGainNarrowband);
+    AT1846S_setPaDrive(cal->PA_drv);
+
+    C6000_setDacRange(cal->dacDataRange);
+    C6000_setMod2Bias(cal->mod2Offset);
+    C6000_setModOffset(cal->mod1Bias);
+
+    uint8_t mod1Amp  = 0;
+    uint8_t sqlTresh = 0;
+    if(band == 0)
+    {
+        /* VHF band */
+        mod1Amp = interpCalParameter(rtxStatus.txFrequency, calData->vhfCalPoints,
+                                     cal->mod1Amplitude, 8);
+
+        sqlTresh = interpCalParameter(rtxStatus.rxFrequency, calData->vhfCalPoints,
+                                     cal->analogSqlThresh, 8);
+    }
+    else
+    {
+        /* UHF band */
+        mod1Amp = interpCalParameter(rtxStatus.txFrequency, calData->uhfMod1CalPoints,
+                                     cal->mod1Amplitude, 8);
+
+        sqlTresh = interpCalParameter(rtxStatus.rxFrequency, calData->uhfMod1CalPoints,
+                                     cal->analogSqlThresh, 8);
+    }
+
+    C6000_setMod1Amplitude(mod1Amp);
+    AT1846S_setAnalogSqlThresh(sqlTresh);
+}
+
+void _setCTCSS()
+{
+    /* TODO */
+}
+
+void _updateSqlThresholds()
+{
+    /* TODO */
+}
+
 void rtx_init(OS_MUTEX *m)
 {
     /* Initialise mutex for configuration access */
@@ -44,6 +236,41 @@ void rtx_init(OS_MUTEX *m)
               (OS_MSG_QTY) 1,
               (OS_ERR   *) &err);
 
+    /*
+     * Configure RTX GPIOs
+     */
+    gpio_setMode(VHF_LNA_EN, OUTPUT);
+    gpio_setMode(UHF_LNA_EN, OUTPUT);
+    gpio_setMode(VHF_PA_EN,  OUTPUT);
+    gpio_setMode(UHF_PA_EN,  OUTPUT);
+
+    gpio_clearPin(VHF_LNA_EN);  /* Turn VHF LNA off */
+    gpio_clearPin(UHF_LNA_EN);  /* Turn UHF LNA off */
+    gpio_clearPin(VHF_PA_EN);   /* Turn VHF PA off  */
+    gpio_clearPin(UHF_PA_EN);   /* Turn UHF PA off  */
+
+    /*
+     * Configure audio control GPIOs
+     */
+    gpio_setMode(AUDIO_AMP_EN, OUTPUT);
+    gpio_setMode(RX_AUDIO_MUX, OUTPUT);
+    gpio_setMode(TX_AUDIO_MUX, OUTPUT);
+
+    gpio_clearPin(AUDIO_AMP_EN);
+    gpio_clearPin(RX_AUDIO_MUX);
+    gpio_clearPin(TX_AUDIO_MUX);
+
+    /*
+     * Load calibration data
+     */
+    calData = ((const gdxCalibration_t *) platform_getCalibrationData());
+
+    /*
+     * Enable and configure both AT1846S and HR_C6000
+     */
+    AT1846S_init();
+    C6000_init();
+
     /*
      * Default initialisation for rtx status
      */
@@ -55,12 +282,17 @@ void rtx_init(OS_MUTEX *m)
     rtxStatus.txFrequency = 430000000;
     rtxStatus.txPower     = 0.0f;
     rtxStatus.sqlLevel    = 1;
+    rtxStatus.rxToneEn    = 0;
     rtxStatus.rxTone      = 0;
+    rtxStatus.txToneEn    = 0;
     rtxStatus.txTone      = 0;
 }
 
 void rtx_terminate()
 {
+    _disableRtxStages();
+    gpio_clearPin(AUDIO_AMP_EN);
+    C6000_terminate();
 }
 
 void rtx_configure(const rtxStatus_t *cfg)
@@ -119,13 +351,58 @@ void rtx_taskFunc()
 
             /* Done, release mutex */
             OSMutexPost(cfgMutex, OS_OPT_POST_NONE, &err);
+
+            /* Update HW configuration */
+            _setOpMode();
+            _setBandwidth();
+            _updateTuningParams();
+            _setCTCSS();
+            _updateSqlThresholds();
+            _setVcoFrequency();
+
+            /* TODO: temporarily force to RX mode if rtx is off. */
+            if(rtxStatus.opStatus == OFF) _enableRxStage();
+        }
+    }
+
+    if(rtxStatus.opStatus == RX)
+    {
+        float sqlLevel  = (rtx_getRssi() + 127.0f)/6.0f;
+
+        float sqlThresh = 7.0f;
+        if(rtxStatus.sqlLevel > 0) sqlThresh = 3.0f;
+
+        if((gpio_readPin(AUDIO_AMP_EN) == 0) && (sqlLevel > (sqlThresh + 0.1f)))
+        {
+            gpio_setPin(AUDIO_AMP_EN);
+            platform_ledOn(GREEN);
         }
 
-        // Do nothing since this is a stub
+        if((gpio_readPin(AUDIO_AMP_EN) == 1) && (sqlLevel < sqlThresh))
+        {
+            gpio_clearPin(AUDIO_AMP_EN);
+            platform_ledOff(GREEN);
+        }
     }
+
+//     if(platform_getPttStatus() && (rtxStatus.opStatus != TX))
+//     {
+//         _disableRtxStages();
+//         _enableTxStage();
+//         platform_ledOn(RED);
+//     }
+//
+//     if(!platform_getPttStatus() && (rtxStatus.opStatus == TX))
+//     {
+//         _disableRtxStages();
+//         _enableRxStage();
+//         platform_ledOff(RED);
+//     }
 }
 
 float rtx_getRssi()
 {
-    return 0.0;
+    uint16_t val = AT1846S_readRSSI();
+    int8_t rssi   = -151 + (val >> 8);
+    return ((float) rssi);
 }
diff --git a/platform/targets/DM-1801/platform.c b/platform/targets/DM-1801/platform.c
index 0cf0d3b7..7db38030 100644
--- a/platform/targets/DM-1801/platform.c
+++ b/platform/targets/DM-1801/platform.c
@@ -19,8 +19,10 @@
  ***************************************************************************/
 
 #include <interfaces/platform.h>
-#include <ADC0_GDx.h>
+#include <interfaces/nvmem.h>
 #include <interfaces/gpio.h>
+#include <calibInfo_GDx.h>
+#include <ADC0_GDx.h>
 #include <I2C0.h>
 #include <os.h>
 #include "hwconfig.h"
@@ -29,6 +31,8 @@
 OS_MUTEX adc_mutex;
 OS_ERR e;
 
+gdxCalibration_t calibration;
+
 void platform_init()
 {
     /* Configure GPIOs */
@@ -70,6 +74,12 @@ void platform_init()
     gpio_setAlternateFunction(I2C_SDA, 3);
     gpio_setAlternateFunction(I2C_SCL, 3);
     i2c0_init();
+
+    /*
+     * Initialise non volatile memory manager and load calibration data.
+     */
+    nvm_init();
+    nvm_readCalibData(&calibration);
 }
 
 void platform_terminate()
@@ -169,3 +179,8 @@ void platform_setBacklightLevel(uint8_t level)
 {
     FTM0->CONTROLS[3].CnV = level;
 }
+
+const void *platform_getCalibrationData()
+{
+    return ((const void *) &calibration);
+}