diff --git a/src/AsyncTCP.cpp b/src/AsyncTCP.cpp
index 471e8fc..59ef186 100644
--- a/src/AsyncTCP.cpp
+++ b/src/AsyncTCP.cpp
@@ -575,11 +575,10 @@ AsyncClient::AsyncClient(tcp_pcb* pcb)
 , _pb_cb_arg(0)
 , _timeout_cb(0)
 , _timeout_cb_arg(0)
-, _pcb_busy(0)
-, _pcb_sent_at(0)
 , _ack_pcb(true)
-, _rx_last_packet(0)
-, _rx_since_timeout(0)
+, _tx_last_packet(0)
+, _rx_timeout(0)
+, _rx_last_ack(0)
 , _ack_timeout(ASYNC_MAX_ACK_TIME)
 , _connect_port(0)
 , prev(NULL)
@@ -783,14 +782,12 @@ size_t AsyncClient::add(const char* data, size_t size, uint8_t apiflags) {
 }
 
 bool AsyncClient::send(){
-    auto pcb_sent_at_backup = _pcb_sent_at;
-    _pcb_sent_at = millis();
-    _pcb_busy++;
+    auto backup = _tx_last_packet;
+    _tx_last_packet = millis();
     if (_tcp_output(_pcb, _closed_slot) == ERR_OK) {
         return true;
     }
-    _pcb_sent_at = pcb_sent_at_backup;
-    _pcb_busy--;
+    _tx_last_packet = backup;
     return false;
 }
 
@@ -870,7 +867,6 @@ int8_t AsyncClient::_connected(void* pcb, int8_t err){
     _pcb = reinterpret_cast<tcp_pcb*>(pcb);
     if(_pcb){
         _rx_last_packet = millis();
-        _pcb_busy = 0;
 //        tcp_recv(_pcb, &_tcp_recv);
 //        tcp_sent(_pcb, &_tcp_sent);
 //        tcp_poll(_pcb, &_tcp_poll, 1);
@@ -932,10 +928,10 @@ int8_t AsyncClient::_fin(tcp_pcb* pcb, int8_t err) {
 
 int8_t AsyncClient::_sent(tcp_pcb* pcb, uint16_t len) {
     _rx_last_packet = millis();
+    _rx_last_ack = millis();
     //log_i("%u", len);
-    _pcb_busy--;
     if(_sent_cb) {
-        _sent_cb(_sent_cb_arg, this, len, (millis() - _pcb_sent_at));
+        _sent_cb(_sent_cb_arg, this, len, (millis() - _tx_last_packet));
     }
     return ERR_OK;
 }
@@ -978,15 +974,18 @@ int8_t AsyncClient::_poll(tcp_pcb* pcb){
     uint32_t now = millis();
 
     // ACK Timeout
-    if(_pcb_busy > 0 && _ack_timeout && (now - _pcb_sent_at) >= _ack_timeout){
-        _pcb_busy = 0;
-        log_w("ack timeout %d", pcb->state);
-        if(_timeout_cb)
-            _timeout_cb(_timeout_cb_arg, this, (now - _pcb_sent_at));
-        return ERR_OK;
+    if(_ack_timeout){
+        const uint32_t one_day = 86400000;
+        bool last_tx_is_after_last_ack = (_rx_last_ack - _tx_last_packet + one_day) < one_day;
+        if(last_tx_is_after_last_ack && (now - _tx_last_packet) >= _ack_timeout) {
+            log_w("ack timeout %d", pcb->state);
+            if(_timeout_cb)
+                _timeout_cb(_timeout_cb_arg, this, (now - _tx_last_packet));
+            return ERR_OK;
+        }
     }
     // RX Timeout
-    if(_rx_since_timeout && (now - _rx_last_packet) >= (_rx_since_timeout * 1000)){
+    if(_rx_timeout && (now - _rx_last_packet) >= (_rx_timeout * 1000)) {
         log_w("rx timeout %d", pcb->state);
         _close();
         return ERR_OK;
@@ -1045,11 +1044,11 @@ size_t AsyncClient::write(const char* data, size_t size, uint8_t apiflags) {
 }
 
 void AsyncClient::setRxTimeout(uint32_t timeout){
-    _rx_since_timeout = timeout;
+    _rx_timeout = timeout;
 }
 
 uint32_t AsyncClient::getRxTimeout(){
-    return _rx_since_timeout;
+    return _rx_timeout;
 }
 
 uint32_t AsyncClient::getAckTimeout(){
diff --git a/src/AsyncTCP.h b/src/AsyncTCP.h
index fcd511b..9786490 100644
--- a/src/AsyncTCP.h
+++ b/src/AsyncTCP.h
@@ -160,12 +160,12 @@ class AsyncClient {
     AcConnectHandler _poll_cb;
     void* _poll_cb_arg;
 
-    uint32_t _pcb_busy;
-    uint32_t _pcb_sent_at;
     bool _ack_pcb;
+    uint32_t _tx_last_packet;
     uint32_t _rx_ack_len;
     uint32_t _rx_last_packet;
-    uint32_t _rx_since_timeout;
+    uint32_t _rx_timeout;
+    uint32_t _rx_last_ack;
     uint32_t _ack_timeout;
     uint16_t _connect_port;