diff --git a/configure.ac b/configure.ac
index 8e49919..6855328 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([mtac], [4.0.6])
+AC_INIT([mtac], [4.0.8])
 AM_INIT_AUTOMAKE
 AM_CONFIG_HEADER([config.h])
 
diff --git a/machine/sam9g25_gpio.h b/machine/sam9g25_gpio.h
index 3848576..eaeb42b 100644
--- a/machine/sam9g25_gpio.h
+++ b/machine/sam9g25_gpio.h
@@ -22,4 +22,9 @@
 #define M_AP2_NRESET AT91_PIN_PB13
 #define M_AP2_NINT1 AT91_PIN_PB17
 #define M_AP2_NINT2 AT91_PIN_PB18
+
+// Special control pins for serial interface
+#define M_AP1_ENABLE_TX_ENABLE AT91_PIN_PC31
+#define M_AP2_ENABLE_TX_ENABLE AT91_PIN_PC30
+
 #endif  /* SAM9G25_MFSER_GPIO_H */
diff --git a/machine/ti43x_gpio.h b/machine/ti43x_gpio.h
index 734998d..3f27e95 100644
--- a/machine/ti43x_gpio.h
+++ b/machine/ti43x_gpio.h
@@ -22,4 +22,10 @@
 #define M_AP2_NRESET OMAP_GPIO(5,29)
 #define M_AP2_NINT1 OMAP_GPIO(3,17)
 #define M_AP2_NINT2 OMAP_GPIO(3,18)
+
+// Special control pins for serial interface
+// which don't exist on the TI platform.
+#define M_AP1_ENABLE_TX_ENABLE 0
+#define M_AP2_ENABLE_TX_ENABLE 0
+
 #endif  /* TI MTCDT3-BB */
diff --git a/mtac.c b/mtac.c
index 2fefc0e..b7b59cd 100644
--- a/mtac.c
+++ b/mtac.c
@@ -1,4 +1,4 @@
-#define DRIVER_VERSION  "v4.0.5"
+#define DRIVER_VERSION  "v4.0.8"
 #define DRIVER_AUTHOR   "Multi-Tech"
 #define DRIVER_DESC "MTS driver to supervise MTAC slots"
 #define DRIVER_NAME "mtac-slots"