diff --git a/bin/mbus-serial-request-data.c b/bin/mbus-serial-request-data.c
index 0e6147a..46526a7 100755
--- a/bin/mbus-serial-request-data.c
+++ b/bin/mbus-serial-request-data.c
@@ -76,7 +76,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         printf("Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-serial-scan.c b/bin/mbus-serial-scan.c
index ac5470a..1d2d0f8 100755
--- a/bin/mbus-serial-scan.c
+++ b/bin/mbus-serial-scan.c
@@ -68,7 +68,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         printf("Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-serial-select-secondary.c b/bin/mbus-serial-select-secondary.c
index 6053056..624a384 100755
--- a/bin/mbus-serial-select-secondary.c
+++ b/bin/mbus-serial-select-secondary.c
@@ -59,7 +59,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         printf("Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-serial-switch-baudrate.c b/bin/mbus-serial-switch-baudrate.c
index 9a4e9bc..e67b98c 100755
--- a/bin/mbus-serial-switch-baudrate.c
+++ b/bin/mbus-serial-switch-baudrate.c
@@ -58,7 +58,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         printf("Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-tcp-request-data-multi-reply.c b/bin/mbus-tcp-request-data-multi-reply.c
index 1a8ff58..7d421f0 100755
--- a/bin/mbus-tcp-request-data-multi-reply.c
+++ b/bin/mbus-tcp-request-data-multi-reply.c
@@ -68,7 +68,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         fprintf(stderr, "Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-tcp-request-data.c b/bin/mbus-tcp-request-data.c
index d2c05fd..1ed504f 100755
--- a/bin/mbus-tcp-request-data.c
+++ b/bin/mbus-tcp-request-data.c
@@ -68,7 +68,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         fprintf(stderr, "Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-tcp-scan-secondary.c b/bin/mbus-tcp-scan-secondary.c
index ab77f67..bd1c12f 100755
--- a/bin/mbus-tcp-scan-secondary.c
+++ b/bin/mbus-tcp-scan-secondary.c
@@ -63,7 +63,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         fprintf(stderr, "Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/bin/mbus-tcp-scan.c b/bin/mbus-tcp-scan.c
index 015c525..2776018 100755
--- a/bin/mbus-tcp-scan.c
+++ b/bin/mbus-tcp-scan.c
@@ -57,7 +57,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         printf("Scan failed: Could not setup connection to M-bus gateway: %s\n",  mbus_error_str());
         return 1;
diff --git a/bin/mbus-tcp-select-secondary.c b/bin/mbus-tcp-select-secondary.c
index ab3cddc..5268650 100755
--- a/bin/mbus-tcp-select-secondary.c
+++ b/bin/mbus-tcp-select-secondary.c
@@ -51,7 +51,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (!mbus_connect(handle))
+    if (mbus_connect(handle) == -1)
     {
         fprintf(stderr, "Failed to setup connection to M-bus gateway\n");
         return 1;
diff --git a/mbus/mbus-protocol-aux.c b/mbus/mbus-protocol-aux.c
index f1b4018..cb11257 100755
--- a/mbus/mbus-protocol-aux.c
+++ b/mbus/mbus-protocol-aux.c
@@ -1408,7 +1408,7 @@ mbus_connect(mbus_handle * handle)
     if (handle == NULL)
     {
         MBUS_ERROR("%s: Invalid M-Bus handle for disconnect.\n", __PRETTY_FUNCTION__);
-        return 0;
+        return -1;
     }
 
     return handle->open(handle);
@@ -1420,7 +1420,7 @@ mbus_disconnect(mbus_handle * handle)
     if (handle == NULL)
     {
         MBUS_ERROR("%s: Invalid M-Bus handle for disconnect.\n", __PRETTY_FUNCTION__);
-        return 0;
+        return -1;
     }
 
     return handle->close(handle);
diff --git a/mbus/mbus-serial.c b/mbus/mbus-serial.c
index 2599676..d28e7eb 100755
--- a/mbus/mbus-serial.c
+++ b/mbus/mbus-serial.c
@@ -37,11 +37,11 @@ mbus_serial_connect(mbus_handle *handle)
     struct termios *term;
 
     if (handle == NULL)
-        return 0;
+        return -1;
 
     serial_data = (mbus_serial_data *) handle->auxdata;
     if (serial_data == NULL || serial_data->device == NULL)
-        return 0;
+        return -1;
 
     device = serial_data->device;
     term = &(serial_data->t);
@@ -53,7 +53,7 @@ mbus_serial_connect(mbus_handle *handle)
     if ((handle->fd = open(device, O_RDWR | O_NOCTTY)) < 0)
     {
         fprintf(stderr, "%s: failed to open tty.", __PRETTY_FUNCTION__);
-        return 0;
+        return -1;
     }
 
     memset(term, 0, sizeof(*term));
@@ -88,7 +88,7 @@ mbus_serial_connect(mbus_handle *handle)
 
     tcsetattr(handle->fd, TCSANOW, term);
 
-    return 1;
+    return 0;
 }
 
 //------------------------------------------------------------------------------
diff --git a/mbus/mbus-tcp.c b/mbus/mbus-tcp.c
index 4234cc0..f81a1cd 100755
--- a/mbus/mbus-tcp.c
+++ b/mbus/mbus-tcp.c
@@ -41,11 +41,11 @@ mbus_tcp_connect(mbus_handle *handle)
     int port;
 
     if (handle == NULL)
-        return 0;
+        return -1;
 
     tcp_data = (mbus_tcp_data *) handle->auxdata;
     if (tcp_data == NULL || tcp_data->host == NULL)
-        return 0;
+        return -1;
 
     host = tcp_data->host;
     port = tcp_data->port;
@@ -57,7 +57,7 @@ mbus_tcp_connect(mbus_handle *handle)
     {
         snprintf(error_str, sizeof(error_str), "%s: failed to setup a socket.", __PRETTY_FUNCTION__);
         mbus_error_str_set(error_str);
-        return 0;
+        return -1;
     }
 
     s.sin_family = AF_INET;
@@ -68,7 +68,7 @@ mbus_tcp_connect(mbus_handle *handle)
     {
         snprintf(error_str, sizeof(error_str), "%s: unknown host: %s", __PRETTY_FUNCTION__, host);
         mbus_error_str_set(error_str);
-        return 0;
+        return -1;
     }
 
     memcpy((void *)(&s.sin_addr), (void *)(host_addr->h_addr), host_addr->h_length);
@@ -77,7 +77,7 @@ mbus_tcp_connect(mbus_handle *handle)
     {
         snprintf(error_str, sizeof(error_str), "%s: Failed to establish connection to %s:%d", __PRETTY_FUNCTION__, host, port);
         mbus_error_str_set(error_str);
-        return 0;
+        return -1;
     }
 
     // Set a timeout
@@ -86,7 +86,7 @@ mbus_tcp_connect(mbus_handle *handle)
     setsockopt(handle->fd, SOL_SOCKET, SO_SNDTIMEO, &time_out, sizeof(time_out));
     setsockopt(handle->fd, SOL_SOCKET, SO_RCVTIMEO, &time_out, sizeof(time_out));
 
-    return 1;
+    return 0;
 }
 
 void