diff --git a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/IStreamIn.aidl b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/IStreamIn.aidl
index 68f1ff3..1041943 100644
--- a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/IStreamIn.aidl
+++ b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/IStreamIn.aidl
@@ -43,7 +43,7 @@
   void updateMetadata(in android.hardware.audio.common.SinkMetadata sinkMetadata);
   float[] getHwGain();
   void setHwGain(in float[] channelGains);
-  const int MIC_FIELD_DIMENSION_WIDE_ANGLE = -1;
+  const int MIC_FIELD_DIMENSION_WIDE_ANGLE = (-1);
   const int MIC_FIELD_DIMENSION_NO_ZOOM = 0;
   const int MIC_FIELD_DIMENSION_MAX_ZOOM = 1;
   const int HW_GAIN_MIN = 0;
diff --git a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/ITelephony.aidl b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/ITelephony.aidl
index a8c58c1..77063df 100644
--- a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/ITelephony.aidl
+++ b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/ITelephony.aidl
@@ -36,4 +36,21 @@
 interface ITelephony {
   android.hardware.audio.core.AudioMode[] getSupportedAudioModes();
   void switchAudioMode(android.hardware.audio.core.AudioMode mode);
+  android.hardware.audio.core.ITelephony.TelecomConfig setTelecomConfig(in android.hardware.audio.core.ITelephony.TelecomConfig config);
+  @JavaDerive(equals=true, toString=true) @VintfStability
+  parcelable TelecomConfig {
+    @nullable android.media.audio.common.Float voiceVolume;
+    android.hardware.audio.core.ITelephony.TelecomConfig.TtyMode ttyMode = android.hardware.audio.core.ITelephony.TelecomConfig.TtyMode.UNSPECIFIED;
+    @nullable android.media.audio.common.Boolean isHacEnabled;
+    const int VOICE_VOLUME_MIN = 0;
+    const int VOICE_VOLUME_MAX = 1;
+    @Backing(type="int") @VintfStability
+    enum TtyMode {
+      UNSPECIFIED = (-1),
+      OFF = 0,
+      FULL = 1,
+      HCO = 2,
+      VCO = 3,
+    }
+  }
 }
diff --git a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/MicrophoneInfo.aidl b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/MicrophoneInfo.aidl
index 68c7f88..b77afe3 100644
--- a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/MicrophoneInfo.aidl
+++ b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/MicrophoneInfo.aidl
@@ -37,15 +37,15 @@
   @utf8InCpp String id;
   android.media.audio.common.AudioDevice device;
   android.hardware.audio.core.MicrophoneInfo.Location location = android.hardware.audio.core.MicrophoneInfo.Location.UNKNOWN;
-  int group = -1;
-  int indexInTheGroup = -1;
+  int group = GROUP_UNKNOWN;
+  int indexInTheGroup = INDEX_IN_THE_GROUP_UNKNOWN;
   @nullable android.hardware.audio.core.MicrophoneInfo.Sensitivity sensitivity;
   android.hardware.audio.core.MicrophoneInfo.Directionality directionality = android.hardware.audio.core.MicrophoneInfo.Directionality.UNKNOWN;
   android.hardware.audio.core.MicrophoneInfo.FrequencyResponsePoint[] frequencyResponse;
   @nullable android.hardware.audio.core.MicrophoneInfo.Coordinate position;
   @nullable android.hardware.audio.core.MicrophoneInfo.Coordinate orientation;
-  const int GROUP_UNKNOWN = -1;
-  const int INDEX_IN_THE_GROUP_UNKNOWN = -1;
+  const int GROUP_UNKNOWN = (-1);
+  const int INDEX_IN_THE_GROUP_UNKNOWN = (-1);
   @Backing(type="int") @VintfStability
   enum Location {
     UNKNOWN = 0,
diff --git a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/StreamDescriptor.aidl b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/StreamDescriptor.aidl
index 3a4271b..a65d7b7 100644
--- a/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/StreamDescriptor.aidl
+++ b/audio/aidl/aidl_api/android.hardware.audio.core/current/android/hardware/audio/core/StreamDescriptor.aidl
@@ -39,12 +39,12 @@
   int frameSizeBytes;
   long bufferSizeFrames;
   android.hardware.audio.core.StreamDescriptor.AudioBuffer audio;
-  const int LATENCY_UNKNOWN = -1;
+  const int LATENCY_UNKNOWN = (-1);
   @FixedSize @VintfStability
   parcelable Position {
-    long frames = -1;
-    long timeNs = -1;
-    const long UNKNOWN = -1;
+    long frames = UNKNOWN;
+    long timeNs = UNKNOWN;
+    const long UNKNOWN = (-1);
   }
   @Backing(type="int") @VintfStability
   enum State {
diff --git a/audio/aidl/android/hardware/audio/core/ITelephony.aidl b/audio/aidl/android/hardware/audio/core/ITelephony.aidl
index a872c7c..a817032 100644
--- a/audio/aidl/android/hardware/audio/core/ITelephony.aidl
+++ b/audio/aidl/android/hardware/audio/core/ITelephony.aidl
@@ -17,6 +17,8 @@
 package android.hardware.audio.core;
 
 import android.hardware.audio.core.AudioMode;
+import android.media.audio.common.Boolean;
+import android.media.audio.common.Float;
 
 /**
  * An instance of ITelephony manages settings which are specific to voice calls
@@ -53,4 +55,75 @@
      * @throws EX_ILLEGAL_STATE If there was an error during switching.
      */
     void switchAudioMode(AudioMode mode);
+
+    @JavaDerive(equals=true, toString=true)
+    @VintfStability
+    parcelable TelecomConfig {
+        const int VOICE_VOLUME_MIN = 0;
+        const int VOICE_VOLUME_MAX = 1;
+        /**
+         * Volume of a voice call. 1.0f means unity gain, 0.0f is muted,
+         * see VOLUME_* constants.
+         */
+        @nullable Float voiceVolume;
+        /**
+         * The current mode of teletypewritter (TTY).
+         */
+        @VintfStability
+        @Backing(type="int")
+        enum TtyMode {
+            /**
+             * The default uninitialized value.
+             */
+            UNSPECIFIED = -1,
+            /**
+             * TTY mode is off.
+             */
+            OFF = 0,
+            /**
+             * TTY mode is on. The speaker is off and the microphone is muted. The
+             * user will communicate with the remote party by sending and receiving
+             * text messages.
+             */
+            FULL = 1,
+            /**
+             * TTY mode is in hearing carryover mode (HCO). The microphone is muted
+             * but the speaker is on. The user will communicate with the remote
+             * party by sending text messages and hearing an audible reply.
+             */
+            HCO = 2,
+            /**
+             * TTY mode is in voice carryover mode (VCO). The speaker is off but the
+             * microphone is still on. User will communicate with the remote party
+             * by speaking and receiving text message replies.
+             */
+            VCO = 3,
+        }
+        TtyMode ttyMode = TtyMode.UNSPECIFIED;
+        /**
+         * Whether Hearing Aid Compatibility - Telecoil (HAC-T) mode is enabled.
+         */
+        @nullable Boolean isHacEnabled;
+    }
+
+    /**
+     * Set the configuration of the telephony audio.
+     *
+     * In the provided parcelable, the client sets zero, one or more parameters
+     * which have to be updated on the HAL side. The parameters that are left
+     * unset must retain their current values.
+     *
+     * In the returned parcelable, all parameter fields known to the HAL module
+     * must be populated to their current values.The client can pass an
+     * uninitialized parcelable in order to retrieve the current configuration.
+     *
+     * @return The current configuration (after update). All fields known to
+     *         the HAL must be populated.
+     * @param config The configuration to set. Any number of fields may be left
+     *               uninitialized.
+     * @throws EX_UNSUPPORTED_OPERATION If telephony is not supported.
+     * @throws EX_ILLEGAL_ARGUMENT If the requested combination of parameter
+     *                             values is invalid.
+     */
+    TelecomConfig setTelecomConfig(in TelecomConfig config);
 }
diff --git a/audio/aidl/default/Telephony.cpp b/audio/aidl/default/Telephony.cpp
index 1854b35..d873178 100644
--- a/audio/aidl/default/Telephony.cpp
+++ b/audio/aidl/default/Telephony.cpp
@@ -20,8 +20,17 @@
 
 #include "core-impl/Telephony.h"
 
+using aidl::android::media::audio::common::Boolean;
+using aidl::android::media::audio::common::Float;
+
 namespace aidl::android::hardware::audio::core {
 
+Telephony::Telephony() {
+    mTelecomConfig.voiceVolume = Float{TelecomConfig::VOICE_VOLUME_MAX};
+    mTelecomConfig.ttyMode = TelecomConfig::TtyMode::OFF;
+    mTelecomConfig.isHacEnabled = Boolean{false};
+}
+
 ndk::ScopedAStatus Telephony::getSupportedAudioModes(std::vector<AudioMode>* _aidl_return) {
     *_aidl_return = mSupportedAudioModes;
     LOG(DEBUG) << __func__ << ": returning " << ::android::internal::ToString(*_aidl_return);
@@ -38,4 +47,28 @@
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
+ndk::ScopedAStatus Telephony::setTelecomConfig(const TelecomConfig& in_config,
+                                               TelecomConfig* _aidl_return) {
+    if (in_config.voiceVolume.has_value() &&
+        (in_config.voiceVolume.value().value < TelecomConfig::VOICE_VOLUME_MIN ||
+         in_config.voiceVolume.value().value > TelecomConfig::VOICE_VOLUME_MAX)) {
+        LOG(ERROR) << __func__
+                   << ": voice volume value is invalid: " << in_config.voiceVolume.value().value;
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    if (in_config.voiceVolume.has_value()) {
+        mTelecomConfig.voiceVolume = in_config.voiceVolume;
+    }
+    if (in_config.ttyMode != TelecomConfig::TtyMode::UNSPECIFIED) {
+        mTelecomConfig.ttyMode = in_config.ttyMode;
+    }
+    if (in_config.isHacEnabled.has_value()) {
+        mTelecomConfig.isHacEnabled = in_config.isHacEnabled;
+    }
+    *_aidl_return = mTelecomConfig;
+    LOG(DEBUG) << __func__ << ": received " << in_config.toString() << ", returning "
+               << _aidl_return->toString();
+    return ndk::ScopedAStatus::ok();
+}
+
 }  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/Telephony.h b/audio/aidl/default/include/core-impl/Telephony.h
index 597f3d6..0936172 100644
--- a/audio/aidl/default/include/core-impl/Telephony.h
+++ b/audio/aidl/default/include/core-impl/Telephony.h
@@ -23,12 +23,18 @@
 namespace aidl::android::hardware::audio::core {
 
 class Telephony : public BnTelephony {
+  public:
+    Telephony();
+
   private:
     ndk::ScopedAStatus getSupportedAudioModes(std::vector<AudioMode>* _aidl_return) override;
     ndk::ScopedAStatus switchAudioMode(AudioMode in_mode) override;
+    ndk::ScopedAStatus setTelecomConfig(const TelecomConfig& in_config,
+                                        TelecomConfig* _aidl_return) override;
 
     const std::vector<AudioMode> mSupportedAudioModes = {::ndk::enum_range<AudioMode>().begin(),
                                                          ::ndk::enum_range<AudioMode>().end()};
+    TelecomConfig mTelecomConfig;
 };
 
 }  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp b/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
index 2508afd..7e1e2b5 100644
--- a/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
+++ b/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
@@ -81,6 +81,7 @@
 using aidl::android::media::audio::common::AudioPortExt;
 using aidl::android::media::audio::common::AudioSource;
 using aidl::android::media::audio::common::AudioUsage;
+using aidl::android::media::audio::common::Float;
 using aidl::android::media::audio::common::Void;
 using android::hardware::audio::common::getChannelCount;
 using android::hardware::audio::common::isBitPositionFlagSet;
@@ -1826,6 +1827,46 @@
     }
 }
 
+TEST_P(AudioCoreTelephony, TelecomConfig) {
+    static const auto kStatuses = {EX_NONE, EX_UNSUPPORTED_OPERATION};
+    if (telephony == nullptr) {
+        GTEST_SKIP() << "Telephony is not supported";
+    }
+    ndk::ScopedAStatus status;
+    ITelephony::TelecomConfig telecomConfig;
+    ASSERT_STATUS(kStatuses, status = telephony->setTelecomConfig({}, &telecomConfig));
+    if (status.getExceptionCode() == EX_UNSUPPORTED_OPERATION) {
+        GTEST_SKIP() << "Telecom is not supported";
+    }
+    EXPECT_TRUE(telecomConfig.voiceVolume.has_value());
+    EXPECT_NE(ITelephony::TelecomConfig::TtyMode::UNSPECIFIED, telecomConfig.ttyMode);
+    EXPECT_TRUE(telecomConfig.isHacEnabled.has_value());
+    ITelephony::TelecomConfig telecomConfig2;
+    ASSERT_IS_OK(telephony->setTelecomConfig(telecomConfig, &telecomConfig2));
+    EXPECT_EQ(telecomConfig, telecomConfig2);
+}
+
+TEST_P(AudioCoreTelephony, TelecomConfigInvalid) {
+    static const auto kStatuses = {EX_NONE, EX_UNSUPPORTED_OPERATION};
+    if (telephony == nullptr) {
+        GTEST_SKIP() << "Telephony is not supported";
+    }
+    ndk::ScopedAStatus status;
+    ITelephony::TelecomConfig telecomConfig;
+    ASSERT_STATUS(kStatuses, status = telephony->setTelecomConfig({}, &telecomConfig));
+    if (status.getExceptionCode() == EX_UNSUPPORTED_OPERATION) {
+        GTEST_SKIP() << "Telecom is not supported";
+    }
+    EXPECT_STATUS(EX_ILLEGAL_ARGUMENT,
+                  telephony->setTelecomConfig(
+                          {.voiceVolume = Float{ITelephony::TelecomConfig::VOICE_VOLUME_MIN - 1}},
+                          &telecomConfig));
+    EXPECT_STATUS(EX_ILLEGAL_ARGUMENT,
+                  telephony->setTelecomConfig(
+                          {.voiceVolume = Float{ITelephony::TelecomConfig::VOICE_VOLUME_MAX + 1}},
+                          &telecomConfig));
+}
+
 using CommandSequence = std::vector<StreamDescriptor::Command>;
 class StreamLogicDriverInvalidCommand : public StreamLogicDriver {
   public: