diff --git a/TODO.txt b/TODO.txt
index 43c8140d4..6e0781199 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -3,8 +3,6 @@
 Last milestone reached: Restart client app without restarting BTdaemon possible
 
 NEXT:
-- automatic HCI link disconnect
-  - periodically (e.g., 5 seconds) close HCI connections without active L2CAP channel
 - automatic turn off Bluetooth after X minutes idle
 - turn off Bluetooth on ctrl-c
 - automatic start/stop of BTdaemon
diff --git a/src/hci.c b/src/hci.c
index 856ac4761..bf2a1da40 100644
--- a/src/hci.c
+++ b/src/hci.c
@@ -15,9 +15,52 @@
 // temp
 #include "l2cap.h"
 
+#define HCI_CONNECTION_TIMEOUT 10
+
 // the STACK is here
 static hci_stack_t       hci_stack;
 
+/**
+ * get connection for a given handle
+ *
+ * @return connection OR NULL, if not found
+ */
+static hci_connection_t * connection_for_handle(hci_con_handle_t con_handle){
+    linked_item_t *it;
+    for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
+        if ( ((hci_connection_t *) it)->con_handle == con_handle){
+            return (hci_connection_t *) it;
+        }
+    }
+    return NULL;
+}
+
+static void hci_connection_timeout_handler(timer_t *timer){
+    hci_connection_t * connection = linked_item_get_user(&timer->item);
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    if (tv.tv_sec > connection->timestamp.tv_sec + HCI_CONNECTION_TIMEOUT) {
+        // connections might be timed out
+        hci_emit_l2cap_check_timeout(connection);
+        run_loop_set_timer(timer, HCI_CONNECTION_TIMEOUT);
+    } else {
+        // next timeout check at
+        timer->timeout.tv_sec = connection->timestamp.tv_sec + HCI_CONNECTION_TIMEOUT;
+    }
+    run_loop_add_timer(timer);
+}
+
+static void hci_connection_timestamp(hci_connection_t *connection){
+    gettimeofday(&connection->timestamp, NULL);
+}
+
+static void hci_connection_update_timestamp_for_acl(uint8_t *packet) {
+    // update timestamp
+    hci_con_handle_t con_handle = READ_ACL_CONNECTION_HANDLE(packet);
+    hci_connection_t *connection = connection_for_handle( con_handle);
+    if (connection) hci_connection_timestamp(connection);
+}
+
 /**
  * create connection for given address
  *
@@ -29,6 +72,9 @@ static hci_connection_t * create_connection_for_addr(bd_addr_t addr){
     BD_ADDR_COPY(conn->address, addr);
     conn->con_handle = 0xffff;
     conn->flags = 0;
+    linked_item_set_user(&conn->timeout.item, conn);
+    conn->timeout.process = hci_connection_timeout_handler;
+    hci_connection_timestamp(conn);
     linked_list_add(&hci_stack.connections, (linked_item_t *) conn);
     return conn;
 }
@@ -48,21 +94,6 @@ static hci_connection_t * connection_for_address(bd_addr_t address){
     return NULL;
 }
 
-/**
- * get connection for a given handle
- *
- * @return connection OR NULL, if not found
- */
-static hci_connection_t * connection_for_handle(hci_con_handle_t con_handle){
-    linked_item_t *it;
-    for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
-        if ( ((hci_connection_t *) it)->con_handle == con_handle){
-            return (hci_connection_t *) it;
-        }
-    }
-    return NULL;
-}
-
 
 /** 
  * Dummy handler called by HCI
@@ -87,7 +118,13 @@ static bt_control_t null_control = {
 }; 
 
 
+int hci_send_acl_packet(uint8_t *packet, int size){
+    hci_connection_update_timestamp_for_acl(packet);
+    return hci_stack.hci_transport->send_acl_packet(packet, size);
+}
+
 static void acl_handler(uint8_t *packet, int size){
+    hci_connection_update_timestamp_for_acl(packet);
     hci_stack.acl_packet_handler(packet, size);
     
     // execute main loop
@@ -114,6 +151,11 @@ static void event_handler(uint8_t *packet, int size){
                 conn->state = OPEN;
                 conn->con_handle = READ_BT_16(packet, 3);
                 conn->flags = 0;
+                
+                gettimeofday(&conn->timestamp, NULL);
+                run_loop_set_timer(&conn->timeout, HCI_CONNECTION_TIMEOUT);
+                run_loop_add_timer(&conn->timeout);
+                
                 printf("New connection: handle %u, ", conn->con_handle);
                 print_bd_addr( conn->address );
                 printf("\n");
@@ -129,6 +171,7 @@ static void event_handler(uint8_t *packet, int size){
                 printf("Connection closed: handle %u, ", conn->con_handle);
                 print_bd_addr( conn->address );
                 printf("\n");
+                run_loop_remove_timer(&conn->timeout);
                 linked_list_remove(&hci_stack.connections, (linked_item_t *) conn);
                 free( conn );
             }
@@ -282,11 +325,6 @@ void hci_run(){
     }
 }
 
-
-int hci_send_acl_packet(uint8_t *packet, int size){
-    return hci_stack.hci_transport->send_acl_packet(packet, size);
-}
-
 int hci_send_cmd_packet(uint8_t *packet, int size){
     bd_addr_t addr;
     hci_connection_t * conn;
@@ -338,6 +376,9 @@ int hci_send_cmd(hci_cmd_t *cmd, ...){
     return hci_send_cmd_packet(hci_cmd_buffer, size);
 }
 
+// Create various non-HCI events. 
+// TODO: generalize, use table similar to hci_create_command
+
 void hci_emit_state(){
     uint8_t len = 3; 
     uint8_t event[len];
@@ -361,3 +402,12 @@ void hci_emit_connection_complete(hci_connection_t *conn){
     hci_stack.event_packet_handler(event, len);
 }
 
+void hci_emit_l2cap_check_timeout(hci_connection_t *conn){
+    uint8_t len = 4; 
+    uint8_t event[len];
+    event[0] = HCI_EVENT_L2CAP_TIMEOUT_CHECK;
+    event[1] = 2;
+    bt_store_16(event, 2, conn->con_handle);
+    hci_dump_packet( HCI_EVENT_PACKET, 0, event, len);
+    hci_stack.event_packet_handler(event, len);
+}
diff --git a/src/hci.h b/src/hci.h
index 7c71de85d..ec31c0d3c 100644
--- a/src/hci.h
+++ b/src/hci.h
@@ -49,6 +49,10 @@ typedef struct {
     // errands
     hci_connection_flags_t flags;
     
+    // timer
+    timer_t timeout;
+    struct timeval timestamp;
+
 } hci_connection_t;
 
 /**
@@ -110,3 +114,4 @@ int hci_send_acl_packet(uint8_t *packet, int size);
 // 
 void hci_emit_state();
 void hci_emit_connection_complete(hci_connection_t *conn);
+void hci_emit_l2cap_check_timeout(hci_connection_t *conn);
diff --git a/src/hci_cmds.h b/src/hci_cmds.h
index 9f68dd888..cf356f08c 100644
--- a/src/hci_cmds.h
+++ b/src/hci_cmds.h
@@ -82,9 +82,14 @@
 
 // data: event (8), len(8), address(48), handle (16), psm (16), source_cid(16), dest_cid (16) 
 #define HCI_EVENT_L2CAP_CHANNEL_OPENED                     0x82
+
 // data: event (8), len(8), channel (16)
 #define HCI_EVENT_L2CAP_CHANNEL_CLOSED                     0x83
 
+// data: event(8), len(8), handle(16)
+#define HCI_EVENT_L2CAP_TIMEOUT_CHECK                      0x84
+
+
 #define COMMAND_COMPLETE_EVENT(event,cmd) ( event[0] == HCI_EVENT_COMMAND_COMPLETE && READ_BT_16(event,3) == cmd.opcode)
 
 #define IS_COMMAND(packet, command) (READ_BT_16(packet,0) == command.opcode)
diff --git a/src/l2cap.c b/src/l2cap.c
index 3bb294d5b..1319d4dd6 100644
--- a/src/l2cap.c
+++ b/src/l2cap.c
@@ -139,6 +139,23 @@ void l2cap_event_handler( uint8_t *packet, uint16_t size ){
         }
     }
     
+    // HCI Connection Timeouts
+    if (packet[0] == HCI_EVENT_L2CAP_TIMEOUT_CHECK){
+        hci_con_handle_t handle = READ_BT_16(packet, 2);
+        linked_item_t *it;
+        l2cap_channel_t * channel;
+        int used = 0;
+        for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){
+            channel = (l2cap_channel_t *) it;
+            if (channel->handle == handle) {
+                used = 1;
+            }
+        }
+        if (!used) {
+            hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closd connection             
+        }
+    }
+    
     // forward to higher layers
     (*event_packet_handler)(packet, size);
     
diff --git a/src/run_loop.c b/src/run_loop.c
index a5aba922f..b2a6d16d6 100644
--- a/src/run_loop.c
+++ b/src/run_loop.c
@@ -23,27 +23,36 @@ void run_loop_set_timer(timer_t *a, int timeout_in_seconds){
 
 // compare timers - NULL is assumed to be before the Big Bang
 // pre: 0 <= tv_usec < 1000000
-int run_loop_timer_compare(timer_t *a, timer_t *b){
-    
+int run_loop_timeval_compare(struct timeval *a, struct timeval *b){
     if (!a || !b) return 0;
     if (!a) return -1;
     if (!b) return 1;
     
-    if (a->timeout.tv_sec < b->timeout.tv_sec) {
+    if (a->tv_sec < b->tv_sec) {
         return -1;
     }
-    if (a->timeout.tv_sec > b->timeout.tv_sec) {
+    if (a->tv_sec > b->tv_sec) {
         return 1;
     }
-
-    if (a->timeout.tv_usec < b->timeout.tv_usec) {
+    
+    if (a->tv_usec < b->tv_usec) {
         return -1;
     }
-    if (a->timeout.tv_usec > b->timeout.tv_usec) {
+    if (a->tv_usec > b->tv_usec) {
         return 1;
     }
     
     return 0;
+    
+}
+
+// compare timers - NULL is assumed to be before the Big Bang
+// pre: 0 <= tv_usec < 1000000
+int run_loop_timer_compare(timer_t *a, timer_t *b){
+    if (!a || !b) return 0;
+    if (!a) return -1;
+    if (!b) return 1;
+    return run_loop_timeval_compare(&a->timeout, &b->timeout);
 }
 
 /**
diff --git a/src/run_loop.h b/src/run_loop.h
index 82d1b8022..41474252f 100644
--- a/src/run_loop.h
+++ b/src/run_loop.h
@@ -25,7 +25,8 @@ typedef struct timer {
 // set timer based on current time
 void run_loop_set_timer(timer_t *a, int timeout_in_seconds);
 
-// compare timers - NULL is assumed to be before the Big Bang
+// compare timeval or timers - NULL is assumed to be before the Big Bang
+int run_loop_timeval_compare(struct timeval *a, struct timeval *b);
 int run_loop_timer_compare(timer_t *a, timer_t *b);
 
 void run_loop_add_data_source(data_source_t *dataSource);     // <-- add DataSource to RunLoop