diff --git a/src/rs232.c b/src/rs232.c
new file mode 100644
index 0000000..90e8818
--- /dev/null
+++ b/src/rs232.c
@@ -0,0 +1,245 @@
+/* OpenBSC BS-11 T-Link interface using POSIX serial port */
+
+/* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <termios.h>
+#include <fcntl.h>
+
+#include <openbsc/select.h>
+#include <openbsc/msgb.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_data.h>
+
+/* adaption layer from GSM 08.59 + 12.21 to RS232 */
+
+struct serial_handle {
+	struct bsc_fd fd;
+	struct llist_head tx_queue;
+
+	struct msgb *rx_msg;
+	unsigned int rxmsg_bytes_missing;
+
+	unsigned int delay_ms;
+};
+
+/* FIXME: this needs to go */
+static struct serial_handle _ser_handle, *ser_handle = &_ser_handle;
+
+#define LAPD_HDR_LEN	10
+
+/* callback from abis_nm */
+int _abis_nm_sendmsg(struct msgb *msg)
+{
+	struct serial_handle *sh = ser_handle;
+	u_int8_t *lapd;
+	unsigned int len;
+
+	msg->l2h = msg->data;
+
+	/* prepend LAPD header */
+	lapd = msgb_push(msg, LAPD_HDR_LEN);
+
+	len = msg->len - 2;
+
+	lapd[0] = (len >> 8) & 0xff;
+	lapd[1] = len & 0xff; /* length of bytes startign at lapd[2] */
+	lapd[2] = 0x00;
+	lapd[3] = 0x07;
+	lapd[4] = 0x01;
+	lapd[5] = 0x3e;
+	lapd[6] = 0x00;
+	lapd[7] = 0x00;
+	lapd[8] = msg->len - 10; /* length of bytes starting at lapd[10] */
+	lapd[9] = lapd[8] ^ 0x38;
+
+	msgb_enqueue(&sh->tx_queue, msg);
+	sh->fd.when |= BSC_FD_WRITE;
+
+	return 0;
+}
+
+/* select.c callback in case we can write to the RS232 */
+static int handle_ser_write(struct bsc_fd *bfd)
+{
+	struct serial_handle *sh = bfd->data;
+	struct msgb *msg;
+	int written;
+
+	msg = msgb_dequeue(&sh->tx_queue);
+	if (!msg) {
+		bfd->when &= ~BSC_FD_WRITE;
+		return 0;
+	}
+
+	if (debug_mask & DMI) {
+		fprintf(stdout, "RS232 TX: ");
+		hexdump(msg->data, msg->len);
+	}
+
+	/* send over serial line */
+	written = write(bfd->fd, msg->data, msg->len);
+	if (written < msg->len) {
+		perror("short write:");
+		msgb_free(msg);
+		return -1;
+	}
+
+	msgb_free(msg);
+	usleep(sh->delay_ms*1000);
+
+	return 0;
+}
+
+#define SERIAL_ALLOC_SIZE	300
+
+/* select.c callback in case we can read from the RS232 */
+static int handle_ser_read(struct bsc_fd *bfd)
+{
+	struct serial_handle *sh = bfd->data;
+	struct msgb *msg;
+	int rc = 0;
+
+	if (!sh->rx_msg) {
+		sh->rx_msg = msgb_alloc(SERIAL_ALLOC_SIZE);
+		sh->rx_msg->l2h = NULL;
+	}
+	msg = sh->rx_msg;
+
+	/* first read two byes to obtain length */
+	if (msg->len < 2) {
+		rc = read(sh->fd.fd, msg->tail, 2 - msg->len);
+		if (rc < 0) {
+			perror("ERROR reading from serial port");
+			msgb_free(msg);
+			return rc;
+		}
+		msgb_put(msg, rc);
+
+		if (msg->len >= 2) {
+			/* parse LAPD payload length */
+			if (msg->data[0] != 0)
+				fprintf(stderr, "Suspicious header byte 0: 0x%02x\n",
+					msg->data[0]);
+
+			sh->rxmsg_bytes_missing = msg->data[0] << 8;
+			sh->rxmsg_bytes_missing += msg->data[1];
+
+			if (sh->rxmsg_bytes_missing < LAPD_HDR_LEN -2)
+				fprintf(stderr, "Invalid length in hdr: %u\n",
+					sh->rxmsg_bytes_missing);
+		}
+	} else { 
+		/* try to read as many of the missing bytes as are available */
+		rc = read(sh->fd.fd, msg->tail, sh->rxmsg_bytes_missing);
+		if (rc < 0) {
+			perror("ERROR reading from serial port");
+			msgb_free(msg);
+			return rc;
+		}
+		msgb_put(msg, rc);
+		sh->rxmsg_bytes_missing -= rc;
+
+		if (sh->rxmsg_bytes_missing == 0) {
+			/* we have one complete message now */
+			sh->rx_msg = NULL;
+
+			if (msg->len > LAPD_HDR_LEN)
+				msg->l2h = msg->data + LAPD_HDR_LEN;
+
+			if (debug_mask & DMI) {
+				fprintf(stdout, "RS232 RX: ");
+				hexdump(msg->data, msg->len);
+			}
+			rc = handle_serial_msg(msg);
+		}
+	}
+
+	return rc;
+}
+
+/* select.c callback */
+static int serial_fd_cb(struct bsc_fd *bfd, unsigned int what)
+{
+	int rc = 0;
+
+	if (what & BSC_FD_READ)
+		rc = handle_ser_read(bfd);
+
+	if (rc < 0)
+		return rc;
+
+	if (what & BSC_FD_WRITE)
+		rc = handle_ser_write(bfd);
+
+	return rc;
+}
+
+int rs232_setup(const char *serial_port, unsigned int delay_ms)
+{
+	int rc, serial_fd;
+	struct termios tio;
+
+	serial_fd = open(serial_port, O_RDWR);
+	if (serial_fd < 0) {
+		perror("cannot open serial port:");
+		return serial_fd;
+	}
+
+	/* set baudrate */
+	rc = tcgetattr(serial_fd, &tio);
+	if (rc < 0) {
+		perror("tcgetattr()");
+		return rc;
+	}
+	cfsetispeed(&tio, B19200);
+	cfsetospeed(&tio, B19200);
+	tio.c_cflag |=  (CREAD | CLOCAL | CS8);
+	tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS);
+	tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
+	tio.c_iflag |=  (INPCK | ISTRIP);
+	tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR);
+	tio.c_oflag &= ~(OPOST);
+	rc = tcsetattr(serial_fd, TCSADRAIN, &tio);
+	if (rc < 0) {
+		perror("tcsetattr()");
+		return rc;
+	}
+
+	INIT_LLIST_HEAD(&ser_handle->tx_queue);
+	ser_handle->fd.fd = serial_fd;
+	ser_handle->fd.when = BSC_FD_READ;
+	ser_handle->fd.cb = serial_fd_cb;
+	ser_handle->fd.data = ser_handle;
+	ser_handle->delay_ms = delay_ms;
+	rc = bsc_register_fd(&ser_handle->fd);
+	if (rc < 0) {
+		fprintf(stderr, "could not register FD: %s\n",
+			strerror(rc));
+		return rc;
+	}
+
+	return 0;
+}