diff --git a/config.h b/config.h
index 86203cf..f9ad5a9 100644
--- a/config.h
+++ b/config.h
@@ -1,4 +1,9 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
+// Choose whether to use KISS or direct
+// framing for serial data
+//#define SERIAL_FRAMING SERIAL_FRAMING_KISS
+#define SERIAL_FRAMING SERIAL_FRAMING_DIRECT
+
 #endif
\ No newline at end of file
diff --git a/device.h b/device.h
index d4358e7..4ee9726 100644
--- a/device.h
+++ b/device.h
@@ -19,7 +19,6 @@
 
 // Serial protocol settings
 #define SERIAL_PROTOCOL PROTOCOL_KISS
-//#define CUSTOM_FRAME_SIZE 330
 
 // Serial settings
 #define BAUD 9600
diff --git a/hardware/AFSK.h b/hardware/AFSK.h
index aecce47..add4a8b 100644
--- a/hardware/AFSK.h
+++ b/hardware/AFSK.h
@@ -42,8 +42,8 @@ inline static uint8_t sinSample(uint16_t i) {
 #define CONFIG_AFSK_RX_BUFLEN 64
 #define CONFIG_AFSK_TX_BUFLEN 64   
 #define CONFIG_AFSK_RXTIMEOUT 0
-#define CONFIG_AFSK_PREAMBLE_LEN 150UL
-#define CONFIG_AFSK_TRAILER_LEN 50UL
+#define CONFIG_AFSK_PREAMBLE_LEN 50UL
+#define CONFIG_AFSK_TRAILER_LEN 5UL
 #define BIT_STUFF_LEN 5
 
 #define SAMPLERATE 9600
diff --git a/main.c b/main.c
index 0a2f111..0836c88 100644
--- a/main.c
+++ b/main.c
@@ -3,6 +3,7 @@
 #include <avr/io.h>
 
 #include "device.h"
+#include "config.h"
 #include "util/FIFO.h"
 #include "util/time.h"
 #include "hardware/AFSK.h"
@@ -48,6 +49,9 @@ int main (void) {
             char sbyte = uart0_getchar_nowait();
             kiss_serialCallback(sbyte);
         }
+        #if SERIAL_FRAMING == SERIAL_FRAMING_DIRECT
+            kiss_checkTimeout(false);
+        #endif
     }
 
     return(0);
diff --git a/protocol/KISS.c b/protocol/KISS.c
index 955c0ed..047cc3a 100644
--- a/protocol/KISS.c
+++ b/protocol/KISS.c
@@ -18,6 +18,7 @@ unsigned long custom_tail = CONFIG_AFSK_TRAILER_LEN;
 
 unsigned long slotTime = 200;
 uint8_t p = 255;
+ticks_t timeout_ticks;
 
 void kiss_init(LLPCtx *ctx, Afsk *afsk, Serial *ser) {
     llpCtx = ctx;
@@ -26,7 +27,7 @@ void kiss_init(LLPCtx *ctx, Afsk *afsk, Serial *ser) {
 }
 
 void kiss_messageCallback(LLPCtx *ctx) {
-    if (false) {
+    if (SERIAL_FRAMING == SERIAL_FRAMING_DIRECT) {
         for (unsigned i = 0; i < ctx->frame_len; i++) {
             uint8_t b = ctx->buf[i];
             fputc(b, &serial->uart0);
@@ -88,41 +89,57 @@ void kiss_csma(LLPCtx *ctx, uint8_t *buf, size_t len) {
     
 }
 
-void kiss_serialCallback(uint8_t sbyte) {
-    if (IN_FRAME && sbyte == FEND && command == CMD_DATA) {
-        IN_FRAME = false;
+void kiss_checkTimeout(bool force) {
+    if (force || (IN_FRAME && timer_clock() - timeout_ticks > ms_to_ticks(TX_MAXWAIT))) {
         kiss_csma(llpCtx, serialBuffer, frame_len);
-    } else if (sbyte == FEND) {
-        IN_FRAME = true;
-        command = CMD_UNKNOWN;
+        IN_FRAME = false;
         frame_len = 0;
-    } else if (IN_FRAME && frame_len < LLP_MAX_FRAME_LENGTH) {
-        // Have a look at the command byte first
-        if (frame_len == 0 && command == CMD_UNKNOWN) {
-            // MicroModem supports only one HDLC port, so we
-            // strip off the port nibble of the command byte
-            sbyte = sbyte & 0x0F;
-            command = sbyte;
-        } else if (command == CMD_DATA) {
-            if (sbyte == FESC) {
-                ESCAPE = true;
-            } else {
-                if (ESCAPE) {
-                    if (sbyte == TFEND) sbyte = FEND;
-                    if (sbyte == TFESC) sbyte = FESC;
-                    ESCAPE = false;
-                }
-                serialBuffer[frame_len++] = sbyte;
-            }
-        } else if (command == CMD_TXDELAY) {
-            custom_preamble = sbyte * 10UL;
-        } else if (command == CMD_TXTAIL) {
-            custom_tail = sbyte * 10;
-        } else if (command == CMD_SLOTTIME) {
-            slotTime = sbyte * 10;
-        } else if (command == CMD_P) {
-            p = sbyte;
-        } 
-        
     }
+    
+}
+
+void kiss_serialCallback(uint8_t sbyte) {
+    #if SERIAL_FRAMING == SERIAL_FRAMING_DIRECT
+        timeout_ticks = timer_clock();
+        IN_FRAME = true;
+        serialBuffer[frame_len++] = sbyte;
+        if (frame_len >= LLP_MAX_FRAME_LENGTH) kiss_checkTimeout(true);
+    #else
+        if (IN_FRAME && sbyte == FEND && command == CMD_DATA) {
+            IN_FRAME = false;
+            kiss_csma(llpCtx, serialBuffer, frame_len);
+        } else if (sbyte == FEND) {
+            IN_FRAME = true;
+            command = CMD_UNKNOWN;
+            frame_len = 0;
+        } else if (IN_FRAME && frame_len < LLP_MAX_FRAME_LENGTH) {
+            // Have a look at the command byte first
+            if (frame_len == 0 && command == CMD_UNKNOWN) {
+                // MicroModem supports only one HDLC port, so we
+                // strip off the port nibble of the command byte
+                sbyte = sbyte & 0x0F;
+                command = sbyte;
+            } else if (command == CMD_DATA) {
+                if (sbyte == FESC) {
+                    ESCAPE = true;
+                } else {
+                    if (ESCAPE) {
+                        if (sbyte == TFEND) sbyte = FEND;
+                        if (sbyte == TFESC) sbyte = FESC;
+                        ESCAPE = false;
+                    }
+                    serialBuffer[frame_len++] = sbyte;
+                }
+            } else if (command == CMD_TXDELAY) {
+                custom_preamble = sbyte * 10UL;
+            } else if (command == CMD_TXTAIL) {
+                custom_tail = sbyte * 10;
+            } else if (command == CMD_SLOTTIME) {
+                slotTime = sbyte * 10;
+            } else if (command == CMD_P) {
+                p = sbyte;
+            } 
+            
+        }
+    #endif
 }
\ No newline at end of file
diff --git a/protocol/KISS.h b/protocol/KISS.h
index ef484a4..45c0c6f 100644
--- a/protocol/KISS.h
+++ b/protocol/KISS.h
@@ -5,6 +5,7 @@
 #include "../hardware/Serial.h"
 #include "../util/time.h"
 #include "LLP.h"
+#include "config.h"
 
 #define FEND 0xC0
 #define FESC 0xDB
@@ -25,5 +26,6 @@ void kiss_init(LLPCtx *ctx, Afsk *afsk, Serial *ser);
 void kiss_csma(LLPCtx *ctx, uint8_t *buf, size_t len);
 void kiss_messageCallback(LLPCtx *ctx);
 void kiss_serialCallback(uint8_t sbyte);
+void kiss_checkTimeout(bool force);
 
 #endif
\ No newline at end of file
diff --git a/protocol/LLP.h b/protocol/LLP.h
index d192d44..a695a42 100644
--- a/protocol/LLP.h
+++ b/protocol/LLP.h
@@ -9,7 +9,7 @@
 
 #define LLP_INTERLEAVE_SIZE 12
 #define LLP_MIN_FRAME_LENGTH LLP_INTERLEAVE_SIZE
-#define LLP_MAX_FRAME_LENGTH 50 * LLP_INTERLEAVE_SIZE
+#define LLP_MAX_FRAME_LENGTH 65 * LLP_INTERLEAVE_SIZE
 #define LLP_HEADER_SIZE 10
 #define LLP_CHECKSUM_SIZE 2
 #define LLP_MAX_DATA_SIZE LLP_MAX_FRAME_LENGTH - LLP_HEADER_SIZE - LLP_CHECKSUM_SIZE // TODO: this is not right
diff --git a/util/constants.h b/util/constants.h
index 6a16a68..2e8b866 100644
--- a/util/constants.h
+++ b/util/constants.h
@@ -6,4 +6,7 @@
 #define m644p  0x03
 
 #define REF_3V3 0x01
-#define REF_5V  0x02
\ No newline at end of file
+#define REF_5V  0x02
+
+#define SERIAL_FRAMING_KISS 0x01
+#define SERIAL_FRAMING_DIRECT 0x02
\ No newline at end of file