diff --git a/Makefile b/Makefile
index d017ed9..9a222b3 100644
--- a/Makefile
+++ b/Makefile
@@ -5,10 +5,8 @@ DEBUG = -g -gdwarf-4
 CFLAGS += -Wall -Werror -Wfatal-errors
 CFLAGS += -std=c2x
 CFLAGS += -I$(SDL)/include -D_REENTRANT
-CFLAGS += -I/usr/local/include
 CFLAGS += $(shell pkg-config --cflags freetype2)
 LDFLAGS += -L$(SDL)/build -lSDL3 -Wl,-rpath=$(SDL)/build
-LDFLAGS += -Wl,-rpath,/usr/local/lib  -L/usr/local/lib -lserialport
 LDFLAGS += $(shell pkg-config --libs freetype2)
 
 DEPFLAGS = -MMD -MP
@@ -18,12 +16,17 @@ OPT = -O3 -march=native
 OBJS = \
 	timer.o
 
-all: main
+SERIAL_FORWARDER_OBJS = \
+	serial_forwarder.o \
+	serial.o \
+	parse_serial.o
+
+all: serial_forwarder
 
 %.o: %.c
 	$(CC) $(CARCH) $(CFLAGS) $(OPT) $(DEBUG) $(DEPFLAGS) -MF ${<}.d -c $< -o $@
 
-main: $(OBJS)
+serial_forwarder: $(SERIAL_FORWARDER_OBJS)
 	$(CC) $(LDFLAGS) $^ -o $@
 
 -include $(shell find -type f -name '*.d')
diff --git a/event.h b/event.h
new file mode 100644
index 0000000..2c80916
--- /dev/null
+++ b/event.h
@@ -0,0 +1,4 @@
+enum command {
+  CMD_NOP,
+  CMD_STATE_TRANSFER,
+};
diff --git a/parse_serial.c b/parse_serial.c
index 29dca90..b35d0c6 100644
--- a/parse_serial.c
+++ b/parse_serial.c
@@ -1,9 +1,10 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdbool.h>
+#include <string.h>
 
 #include "packet.h"
-#include "bufsize.h"
+#include "parse_serial.h"
 
 uint8_t const * parse_int(uint8_t const * buf, int * length, int * number, int * digits)
 {
@@ -27,8 +28,8 @@ uint8_t const * parse_int(uint8_t const * buf, int * length, int * number, int *
     case '8': [[fallthrough]];
     case '9':
       *digits += 1;
-      number *= 10;
-      number += c - '0';
+      *number *= 10;
+      *number += c - '0';
       break;
     case ' ':
       break;
@@ -49,7 +50,7 @@ int parse_time(uint8_t const * const buf, int length, struct stopwatch_time * ti
   uint8_t const * bufi = buf;
   bufi = parse_int(bufi, &length, &time->integer_value, &time->integer_digits);
 
-  if (integer_digits == 0) {
+  if (time->integer_digits == 0) {
     fprintf(stderr, "invalid integer at `%c`\n", *bufi);
     return -1;
   }
@@ -62,7 +63,7 @@ int parse_time(uint8_t const * const buf, int length, struct stopwatch_time * ti
     return -1;
 
   bufi = parse_int(bufi, &length, &time->fraction_value, &time->fraction_digits);
-  if (integer_digits == 0) {
+  if (time->fraction_digits == 0) {
     fprintf(stderr, "invalid fraction at `%c`\n", *bufi);
     return -1;
   }
@@ -74,55 +75,65 @@ int min(int a, int b) {
   return a < b ? a : b;
 }
 
-struct parser_state {
-  uint8_t buf[BUFSIZE];
-  int offset;
-};
-
-bool is_()
+bool is_timer_resume(uint8_t const * const buf, int length)
 {
+  return false;
 }
 
-void parse_line(uint8_t * buf, int length,
-		struct timer_state * timer_state)
+bool handle_line(uint8_t const * const buf, int length,
+                 struct timer_state * timer_state)
 {
   if (length == 0) {
-    timer_state->status = COUNTER_RUNNING;
+    timer_state->status = TIMER_RUNNING;
     int ret = clock_gettime(CLOCK_MONOTONIC, &timer_state->counter.start);
     timer_state->counter.offset.tv_sec = 0;
     timer_state->counter.offset.tv_nsec = 0;
     assert(ret != -1);
-  } else if (is_) {
+    return true;
+  } else if (is_timer_resume(buf, length)) {
+    return true;
+  } else {
+    int ret = parse_time(buf, length, &timer_state->time);
+    if (ret == 0) {
+      timer_state->status = TIMER_STOPPED;
+      return true;
+    }
   }
+
+  return false;
 }
 
-void handle_parse(uint8_t * read_buf, int length,
+bool handle_parse(uint8_t * read_buf, int length,
 		  struct parser_state * parser_state,
 		  struct timer_state * timer_state)
 {
+  bool have_state_change = false;
   while (length > 0) {
-    int copy_length = min(length, BUFSIZE - state->offset);
+    int copy_length = min(length, BUFSIZE - parser_state->offset);
     length -= copy_length;
-    memcpy(&state->buf[state->offset], read_buf, copy_length);
-    state->offset += copy_length;
+    memcpy(&parser_state->buf[parser_state->offset], read_buf, copy_length);
+    parser_state->offset += copy_length;
 
-    while (state->offset > 0) {
+    while (parser_state->offset > 0) {
       int i = 0;
-      while (i < state->offset) {
-	if (state->buf[i] == '\r') {
-	  fprintf(stderr, "r at %d %d\n", i, state->offset);
-	  handle_line(state->buf, i);
-	  state->offset -= i + 1;
-	  assert(state->offset >= 0);
-	  memmove(&state->buf[0], &state->buf[i + 1], state->offset);
+      while (i < parser_state->offset) {
+	if (parser_state->buf[i] == '\r') {
+	  fprintf(stderr, "r at %d %d\n", i, parser_state->offset);
+          have_state_change |= handle_line(parser_state->buf, i,
+                                           timer_state);
+	  parser_state->offset -= i + 1;
+	  assert(parser_state->offset >= 0);
+	  memmove(&parser_state->buf[0], &parser_state->buf[i + 1], parser_state->offset);
 	  break;
 	}
 	i++;
-	if (i == state->offset)
+	if (i == parser_state->offset)
 	  goto exit;
       }
     }
   exit:
     continue;
   }
+
+  return have_state_change;
 }
diff --git a/parse_serial.h b/parse_serial.h
new file mode 100644
index 0000000..72af749
--- /dev/null
+++ b/parse_serial.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+#include "bufsize.h"
+#include "timer.h"
+
+struct parser_state {
+  uint8_t buf[BUFSIZE];
+  int offset;
+};
+
+bool handle_parse(uint8_t * read_buf, int length,
+		  struct parser_state * parser_state,
+		  struct timer_state * timer_state);
diff --git a/serial.c b/serial.c
new file mode 100644
index 0000000..9139eaa
--- /dev/null
+++ b/serial.c
@@ -0,0 +1,50 @@
+#define _DEFAULT_SOURCE 1
+
+#include <termios.h>
+#include <stdio.h>
+
+#include "serial.h"
+
+int set_terminal_attributes(int fd)
+{
+  int ret;
+  struct termios tty;
+  ret = tcgetattr(fd, &tty);
+  if (ret == -1) {
+    perror("tcgetattr");
+    return -1;
+  }
+
+  tty.c_cflag &= ~PARENB; // no parity
+  tty.c_cflag &= ~CSTOPB; // one stop bit
+  tty.c_cflag &= ~CSIZE; // clear size bits
+  tty.c_cflag |= CS8; // 8 bit
+  tty.c_cflag &= ~CRTSCTS; // disable RTS/CTS hardware flow control
+  tty.c_cflag |= CREAD | CLOCAL; // turn on READ & ignore ctrl lines
+
+  tty.c_lflag &= ~ICANON;
+  tty.c_lflag &= ~ECHO; // disable echo
+  tty.c_lflag &= ~ECHOE; // disable erasure
+  tty.c_lflag &= ~ECHONL; // disable new-line echo
+  tty.c_lflag &= ~ISIG; // disable interpretation of INTR, QUIT and SUSP
+
+  tty.c_iflag &= ~(IXON|IXOFF|IXANY); // turn off xon/xoff ctrl
+  tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL); // disable any special handling of received bytes
+
+  tty.c_oflag &= ~OPOST; // prevent special interpretation of output bytes (e.g. newline chars)
+  tty.c_oflag &= ~ONLCR; // prevent conversion of newline to carriage return/line feed
+
+  tty.c_cc[VMIN] = 1;
+  tty.c_cc[VTIME] = 0;
+
+  cfsetospeed(&tty, B1200);
+  cfsetispeed(&tty, B1200);
+
+  ret = tcsetattr(fd, TCSANOW, &tty);
+  if (ret == -1) {
+    perror("tcsetattr");
+    return -1;
+  }
+
+  return 0;
+}
diff --git a/serial.h b/serial.h
new file mode 100644
index 0000000..0a84f04
--- /dev/null
+++ b/serial.h
@@ -0,0 +1,3 @@
+#pragma once
+
+int set_terminal_attributes(int fd);
diff --git a/serial_forwarder b/serial_forwarder
new file mode 100755
index 0000000..355dcf9
Binary files /dev/null and b/serial_forwarder differ
diff --git a/serial_forwarder.c b/serial_forwarder.c
index 761f9b2..b2d75a0 100644
--- a/serial_forwarder.c
+++ b/serial_forwarder.c
@@ -1,79 +1,23 @@
+#include <arpa/inet.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
-#include <arpa/inet.h>
-#include <sys/socket.h>
 #include <sys/epoll.h>
-#include <errno.h>
-#include <stdbool.h>
-
-#include <libserialport.h>
+#include <sys/socket.h>
+#include <sys/timerfd.h>
+#include <unistd.h>
 
 #include "bufsize.h"
+#include "serial.h"
+#include "timer.h"
+#include "parse_serial.h"
 
 #define PORT 4321
-#define SERIALPORT "/dev/ttyS0"
-
-int sp_error(const char * s, enum sp_return result)
-{
-  char * error_message;
-  switch (result) {
-  case SP_ERR_ARG:
-    printf("%s: error: Invalid argument.\n", s);
-  case SP_ERR_FAIL:
-    error_message = sp_last_error_message();
-    printf("%s: error: Failed: %s\n", error_message, s);
-    sp_free_error_message(error_message);
-  case SP_ERR_SUPP:
-    printf("%s: error: Not supported.\n", s);
-  case SP_ERR_MEM:
-    printf("%s: error: Couldn't allocate memory.\n", s);
-  case SP_OK: [[fallthrough]];
-  default:
-    return result;
-  }
-}
-
-int init_serial(struct sp_port * port)
-{
-  enum sp_return sp_ret;
-
-  sp_ret = sp_get_port_by_name(SERIALPORT, &port);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_get_port_by_name", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_open(port, SP_MODE_READ_WRITE);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_open", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_set_baudrate(port, 1200);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_set_baudrate", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_set_bits(port, 8);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_set_bits", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_set_parity(port, SP_PARITY_NONE);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_set_parity", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_set_stopbits(port, 1);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_set_stopbits", sp_ret);
-    return -1;
-  }
-  sp_ret = sp_set_flowcontrol(port, SP_FLOWCONTROL_NONE);
-  if (sp_ret != SP_OK) {
-    sp_error("sp_set_flowcontrol", sp_ret);
-    return -1;
-  }
-}
+//#define SERIALPORT "/dev/ttyS0"
+#define SERIALPORT "/dev/ttyUSB0"
 
 int handle_sock(int sock)
 {
@@ -86,10 +30,10 @@ int handle_sock(int sock)
     ssize_t recv_len = recvfrom(sock, buf, BUFSIZE, 0, (struct sockaddr *)&src_addr, &addrlen);
     if (recv_len == -1) {
       if (errno == EAGAIN || errno == EWOULDBLOCK) {
-	perror("eagain");
+	perror("sock eagain");
 	return 0;
       } else {
-	perror("recvfrom");
+	perror("recvfrom sock");
 	return -1;
       }
     }
@@ -101,11 +45,85 @@ int handle_sock(int sock)
   }
 }
 
+int rearm_timer(int timerfd)
+{
+  struct itimerspec value;
+  value.it_value.tv_sec = 1;
+  value.it_value.tv_nsec = 0;
+  value.it_interval.tv_sec = 0;
+  value.it_interval.tv_nsec = 0;
+
+  int ret = timerfd_settime(timerfd, 0, &value, NULL);
+  if (ret == -1) {
+    perror("timerfd_settime");
+    return -1;
+  }
+
+  return 0;
+}
+
+int handle_timerfd(int timerfd)
+{
+  uint64_t expired_count = 0;
+  while (true) {
+    ssize_t len = read(timerfd, &expired_count, (sizeof (expired_count)));
+    if (len == -1) {
+      if (errno == EAGAIN || errno == EWOULDBLOCK) {
+        fprintf(stderr, "timerfd eagain\n");
+	break;
+      } else {
+	perror("read timerfd");
+	return -1;
+      }
+    }
+    assert(len == (sizeof (expired_count)));
+    printf("len %ld\n", len);
+  }
+
+  rearm_timer(timerfd);
+  printf("do timer stuff\n");
+
+  return 0;
+}
+
 struct receiver_state {
   uint64_t seq;
   uint64_t ack_seq;
 };
 
+int handle_serialfd(int timerfd,
+                    struct parser_state * parser_state,
+                    struct timer_state * timer_state)
+{
+  uint8_t buf[BUFSIZE];
+
+  while (true) {
+    ssize_t len = read(timerfd, buf, (sizeof (buf)));
+    if (len == -1) {
+      if (errno == EAGAIN || errno == EWOULDBLOCK) {
+        fprintf(stderr, "serialfd eagain\n");
+        break;
+      } else {
+	perror("read serialfd");
+	return -1;
+      }
+    }
+
+    /*
+    for (int i = 0; i < len; i++) {
+      fprintf(stderr, "%x ", buf[i]);
+    }
+    fprintf(stderr, "\n");
+    */
+    bool have_state_change = handle_parse(buf, len,
+                                          parser_state,
+                                          timer_state);
+    printf("have_state_change: %d\n", have_state_change);
+  }
+
+  return 0;
+}
+
 int main(void)
 {
   int ret;
@@ -127,7 +145,7 @@ int main(void)
     return -1;
   }
 
-#define MAX_EVENTS 2
+#define MAX_EVENTS 5
   struct epoll_event events[MAX_EVENTS];
 
   int epollfd = epoll_create1(0);
@@ -136,19 +154,67 @@ int main(void)
     return -1;
   }
 
-  struct epoll_event ev;
-  ev.events = EPOLLIN | EPOLLET;
-  ev.data.fd = sock;
-  ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, sock, &ev);
-  if (ret == -1) {
-    perror("epoll_ctl: sock");
+  {
+    struct epoll_event ev;
+    ev.events = EPOLLIN | EPOLLET;
+    ev.data.fd = sock;
+    ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, sock, &ev);
+    if (ret == -1) {
+      perror("epoll_ctl: sock");
+      return -1;
+    }
+  }
+
+  int timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+  if (timerfd == -1) {
+    perror("timerfd_create");
     return -1;
   }
 
+  ret = rearm_timer(timerfd);
+  if (ret == -1) {
+    return -1;
+  }
+
+  if (0) {
+    struct epoll_event ev;
+    ev.events = EPOLLIN | EPOLLET;
+    ev.data.fd = timerfd;
+    ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, timerfd, &ev);
+    if (ret == -1) {
+      perror("epoll_ctl: timerfd");
+      return -1;
+    }
+  }
+
+  int serialfd = open(SERIALPORT, O_RDWR | O_NOCTTY | O_NONBLOCK);
+  if (serialfd == -1) {
+    perror("open: serialport");
+    return -1;
+  }
+  ret = set_terminal_attributes(serialfd);
+  if (ret == -1) {
+    return -1;
+  }
+
+  {
+    struct epoll_event ev;
+    ev.events = EPOLLIN | EPOLLET;
+    ev.data.fd = serialfd;
+    ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, serialfd, &ev);
+    if (ret == -1) {
+      perror("epoll_ctl: timerfd");
+      return -1;
+    }
+  }
+
+  struct parser_state parser_state = {0};
+  struct timer_state timer_state = {0};
+
   while (1) {
     printf("Wait for datagram\n");
 
-    int nfds = epoll_wait(epollfd, events, MAX_EVENTS, 1000);
+    int nfds = epoll_wait(epollfd, events, MAX_EVENTS, -1);
     if (nfds == -1) {
       perror("epoll_wait");
       return -1;
@@ -159,6 +225,19 @@ int main(void)
 	ret = handle_sock(sock);
 	if (ret == -1)
 	  return -1;
+      } else if (events[n].data.fd == timerfd) {
+        ret = handle_timerfd(timerfd);
+        if (ret == -1)
+          return -1;
+      } else if (events[n].data.fd == serialfd) {
+        fprintf(stderr, "handle_serialfd\n");
+        ret = handle_serialfd(serialfd,
+                              &parser_state,
+                              &timer_state);
+        if (ret == -1)
+          return -1;
+      } else {
+        assert(0);
       }
     }
 
diff --git a/timer.h b/timer.h
index e3bf079..61df870 100644
--- a/timer.h
+++ b/timer.h
@@ -1,13 +1,17 @@
+#pragma once
+
 #include <time.h>
 
-enum counter_status {
-  COUNTER_STOPPED,
-  COUNTER_RUNNING,
+enum timer_status {
+  TIMER_STOPPED,
+  TIMER_RUNNING,
 };
 
 struct stopwatch_time {
-  int32_t whole;
-  int32_t fraction;
+  int integer_value;
+  int integer_digits;
+  int fraction_value;
+  int fraction_digits;
 };
 
 struct running_counter {
@@ -16,7 +20,7 @@ struct running_counter {
 };
 
 struct timer_state {
-  enum counter_status status;
+  enum timer_status status;
   struct running_counter counter;
   struct stopwatch_time time;
 };