diff --git a/third-party/realdds/src/dds-device-impl.cpp b/third-party/realdds/src/dds-device-impl.cpp
index 6dd10f1511..a79d99237e 100644
--- a/third-party/realdds/src/dds-device-impl.cpp
+++ b/third-party/realdds/src/dds-device-impl.cpp
@@ -85,7 +85,7 @@ dds_device::impl::impl( std::shared_ptr< dds_participant > const & participant,
     , _subscriber( std::make_shared< dds_subscriber >( participant ) )
     , _device_settings( device_settings( participant ) )
     , _reply_timeout_ms(
-          _device_settings.nested( "control", "reply-timeout-ms" ).default_value< size_t >( 2000 ) )
+          _device_settings.nested( "control", "reply-timeout-ms" ).default_value< size_t >( 2500 ) )
 {
     create_control_writer();
     create_notifications_reader();
@@ -564,6 +564,9 @@ void dds_device::impl::create_control_writer()
     _control_writer = std::make_shared< dds_topic_writer >( topic );
     dds_topic_writer::qos wqos( eprosima::fastdds::dds::RELIABLE_RELIABILITY_QOS );
     wqos.history().depth = 10;  // default is 1
+    // If our reply timeout is less than the heartbeat period, we could lose the control message!
+    // So we set a short heartbeat time at half the reply timeout...
+    wqos.reliable_writer_qos().times.heartbeatPeriod = _reply_timeout_ms / 2000.;
     _control_writer->override_qos_from_json( wqos, _device_settings.nested( "control" ) );
     _control_writer->run( wqos );
 }
diff --git a/third-party/realdds/src/dds-topic-writer.cpp b/third-party/realdds/src/dds-topic-writer.cpp
index 7051b44f38..11f9ee8cd5 100644
--- a/third-party/realdds/src/dds-topic-writer.cpp
+++ b/third-party/realdds/src/dds-topic-writer.cpp
@@ -92,6 +92,8 @@ void dds_topic_writer::override_qos_from_json( qos & wqos, rsutils::json const &
     // Default values should be set before we're called:
     // All we do here is override those - if specified!
     override_reliability_qos_from_json( wqos.reliability(), qos_settings.nested( "reliability" ) );
+    if( wqos.reliability().kind == eprosima::fastdds::dds::RELIABLE_RELIABILITY_QOS )
+        qos_settings.nested( "heartbeat-period" ).get_ex( wqos.reliable_writer_qos().times.heartbeatPeriod );
     override_durability_qos_from_json( wqos.durability(), qos_settings.nested( "durability" ) );
     override_history_qos_from_json( wqos.history(), qos_settings.nested( "history" ) );
     override_liveliness_qos_from_json( wqos.liveliness(), qos_settings.nested( "liveliness" ) );