diff --git a/examples/ggwave-cli/main.cpp b/examples/ggwave-cli/main.cpp
index fff813d..9be6e68 100644
--- a/examples/ggwave-cli/main.cpp
+++ b/examples/ggwave-cli/main.cpp
@@ -18,6 +18,7 @@ int main(int argc, char** argv) {
     printf("    -pN - select playback device N\n");
     printf("    -tN - transmission protocol\n");
     printf("    -lN - fixed payload length of size N, N in [1, %d]\n", GGWave::kMaxLengthFixed);
+    printf("    -v  - print generated tones on resend\n");
     printf("\n");
 
     auto argm = parseCmdArguments(argc, argv);
@@ -25,6 +26,7 @@ int main(int argc, char** argv) {
     int playbackId = argm["p"].empty() ? 0 : std::stoi(argm["p"]);
     int txProtocol = argm["t"].empty() ? 1 : std::stoi(argm["t"]);
     int payloadLength = argm["l"].empty() ? -1 : std::stoi(argm["l"]);
+    bool printTones = argm.find("v") == argm.end() ? false : true;
 
     if (GGWave_init(playbackId, captureId, payloadLength) == false) {
         fprintf(stderr, "Failed to initialize GGWave\n");
@@ -51,13 +53,26 @@ int main(int argc, char** argv) {
         std::string inputOld = "";
         while (true) {
             std::string input;
-            std::cout << "Enter text: ";
+            printf("Enter text: ");
+            fflush(stdout);
             getline(std::cin, input);
             if (input.empty()) {
-                std::cout << "Re-sending ... " << std::endl;
+                printf("Re-sending ...\n");
                 input = inputOld;
+
+                if (printTones) {
+                    printf("Printing generated waveform tones (Hz):\n");
+                    auto waveformTones = ggWave->getWaveformTones();
+                    for (int i = 0; i < (int) waveformTones.size(); ++i) {
+                        printf(" - frame %3d: ", i);
+                        for (int j = 0; j < (int) waveformTones[i].size(); ++j) {
+                            printf("%8.2f ", waveformTones[i][j].freq_hz);
+                        }
+                        printf("\n");
+                    }
+                }
             } else {
-                std::cout << "Sending ... " << std::endl;
+                printf("Sending ...\n");
             }
             {
                 std::lock_guard<std::mutex> lock(mutex);
diff --git a/include/ggwave/ggwave.h b/include/ggwave/ggwave.h
index 668df15..58f7d37 100644
--- a/include/ggwave/ggwave.h
+++ b/include/ggwave/ggwave.h
@@ -275,6 +275,14 @@ class GGWave {
         return kTxProtocols;
     }
 
+    struct ToneData {
+        double freq_hz;
+        double duration_ms;
+    };
+
+    using Tones = std::vector<ToneData>;
+    using WaveformTones = std::vector<Tones>;
+
     using AmplitudeData    = std::vector<float>;
     using AmplitudeDataI16 = std::vector<int16_t>;
     using SpectrumData     = std::vector<float>;
@@ -355,6 +363,12 @@ class GGWave {
     static const TxProtocol & getTxProtocol(int id)  { return getTxProtocols().at(TxProtocolId(id)); }
     static const TxProtocol & getTxProtocol(TxProtocolId id) { return getTxProtocols().at(id); }
 
+    // get a list of the tones generated for the last waveform
+    //
+    //   Call this method after calling encode() to get a list of the tones participating in the generated waveform
+    //
+    const WaveformTones & getWaveformTones() { return m_waveformTones; }
+
     bool takeTxAmplitudeI16(AmplitudeDataI16 & dst);
 
     // Rx
@@ -473,6 +487,7 @@ class GGWave {
     TxRxData m_outputBlockTmp;
     AmplitudeDataI16 m_outputBlockI16;
     AmplitudeDataI16 m_txAmplitudeDataI16;
+    WaveformTones m_waveformTones;
 
     // Impl
     // todo : move all members inside Impl
diff --git a/src/ggwave.cpp b/src/ggwave.cpp
index 3a54ee6..2f7b914 100644
--- a/src/ggwave.cpp
+++ b/src/ggwave.cpp
@@ -546,18 +546,26 @@ bool GGWave::encode(const CBWaveformOut & cbWaveformOut) {
     float factor = kBaseSampleRate/m_sampleRateOut;
     uint32_t offset = 0;
 
+    m_waveformTones.clear();
+
     while (m_hasNewTxData) {
         std::fill(m_outputBlock.begin(), m_outputBlock.end(), 0.0f);
 
         std::uint16_t nFreq = 0;
+        m_waveformTones.push_back({});
+
         if (frameId < m_nMarkerFrames) {
             nFreq = m_nBitsInMarker;
 
             for (int i = 0; i < m_nBitsInMarker; ++i) {
+                m_waveformTones.back().push_back({});
+                m_waveformTones.back().back().duration_ms = (1000.0*m_samplesPerFrame)/kBaseSampleRate;
                 if (i%2 == 0) {
                     ::addAmplitudeSmooth(bit1Amplitude[i], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, frameId, m_nMarkerFrames);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, i);
                 } else {
                     ::addAmplitudeSmooth(bit0Amplitude[i], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, frameId, m_nMarkerFrames);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, i) + m_hzPerSample;
                 }
             }
         } else if (frameId < m_nMarkerFrames + totalDataFrames) {
@@ -583,10 +591,14 @@ bool GGWave::encode(const CBWaveformOut & cbWaveformOut) {
                 if (dataBits[k] == 0) continue;
 
                 ++nFreq;
+                m_waveformTones.back().push_back({});
+                m_waveformTones.back().back().duration_ms = (1000.0*m_samplesPerFrame)/kBaseSampleRate;
                 if (k%2) {
                     ::addAmplitudeSmooth(bit0Amplitude[k/2], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, cycleModMain, m_txProtocol.framesPerTx);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, k/2) + m_hzPerSample;
                 } else {
                     ::addAmplitudeSmooth(bit1Amplitude[k/2], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, cycleModMain, m_txProtocol.framesPerTx);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, k/2);
                 }
             }
         } else if (frameId < m_nMarkerFrames + totalDataFrames + m_nMarkerFrames) {
@@ -594,10 +606,14 @@ bool GGWave::encode(const CBWaveformOut & cbWaveformOut) {
 
             int fId = frameId - (m_nMarkerFrames + totalDataFrames);
             for (int i = 0; i < m_nBitsInMarker; ++i) {
+                m_waveformTones.back().push_back({});
+                m_waveformTones.back().back().duration_ms = (1000.0*m_samplesPerFrame)/kBaseSampleRate;
                 if (i%2 == 0) {
                     addAmplitudeSmooth(bit0Amplitude[i], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, fId, m_nMarkerFrames);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, i) + m_hzPerSample;
                 } else {
                     addAmplitudeSmooth(bit1Amplitude[i], m_outputBlock, m_sendVolume, 0, m_samplesPerFrame, fId, m_nMarkerFrames);
+                    m_waveformTones.back().back().freq_hz = bitFreq(m_txProtocol, i);
                 }
             }
         } else {