diff --git a/src/sysmo_l1_if.h b/src/sysmo_l1_if.h
new file mode 100644
index 0000000..49bbb62
--- /dev/null
+++ b/src/sysmo_l1_if.h
@@ -0,0 +1,81 @@
+#ifndef _SYSMO_L1_IF_H
+#define _SYSMO_L1_IF_H
+
+#include <osmocom/core/select.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/gsmtap_util.h>
+#include <osmocom/gsm/gsm_utils.h>
+#include "femtobts.h"
+
+enum {
+	MQ_SYS_READ,
+	MQ_L1_READ,
+#ifndef HW_SYSMOBTS_V1
+	MQ_TCH_READ,
+	MQ_PDTCH_READ,
+#endif
+	_NUM_MQ_READ
+};
+
+enum {
+	MQ_SYS_WRITE,
+	MQ_L1_WRITE,
+#ifndef HW_SYSMOBTS_V1
+	MQ_TCH_WRITE,
+	MQ_PDTCH_WRITE,
+#endif
+	_NUM_MQ_WRITE
+};
+
+struct femtol1_hdl {
+	struct gsm_time gsm_time;
+	uint32_t hLayer1;			/* handle to the L1 instance in the DSP */
+	uint32_t dsp_trace_f;
+	int clk_cal;
+	uint8_t clk_src;
+	struct llist_head wlc_list;
+
+	struct gsmtap_inst *gsmtap;
+	uint32_t gsmtap_sapi_mask;
+
+	void *priv;			/* user reference */
+
+	struct osmo_timer_list alive_timer;
+	unsigned int alive_prim_cnt;
+
+	struct osmo_fd read_ofd[_NUM_MQ_READ];	/* osmo file descriptors */
+	struct osmo_wqueue write_q[_NUM_MQ_WRITE];
+
+	struct {
+		uint8_t dsp_version[3];
+		uint8_t fpga_version[3];
+		uint32_t band_support;	/* bitmask of GSM_BAND_* */
+	} hw_info;
+};
+
+#define msgb_l1prim(msg)	((GsmL1_Prim_t *)(msg)->l1h)
+#define msgb_sysprim(msg)	((SuperFemto_Prim_t *)(msg)->l1h)
+
+typedef int l1if_compl_cb(struct msgb *l1_msg, void *data);
+
+/* send a request primitive to the L1 and schedule completion call-back */
+int l1if_req_compl(struct femtol1_hdl *fl1h, struct msgb *msg,
+		   int is_system_prim, l1if_compl_cb *cb, void *data);
+
+int l1if_reset(struct femtol1_hdl *hdl);
+int l1if_activate_rf(struct femtol1_hdl *hdl, int on);
+int l1if_set_trace_flags(struct femtol1_hdl *hdl, uint32_t flags);
+int l1if_set_txpower(struct femtol1_hdl *fl1h, float tx_power);
+
+struct msgb *l1p_msgb_alloc(void);
+struct msgb *sysp_msgb_alloc(void);
+
+uint32_t l1if_lchan_to_hLayer2(struct gsm_lchan *lchan);
+struct gsm_lchan *l1if_hLayer2_to_lchan(struct gsm_bts_trx *trx, uint32_t hLayer2);
+
+/* tch.c */
+int l1if_tch_rx(struct gsm_lchan *lchan, struct msgb *l1p_msg);
+int l1if_tch_fill(struct gsm_lchan *lchan, uint8_t *l1_buffer);
+struct msgb *gen_empty_tch_msg(struct gsm_lchan *lchan);
+
+#endif /* _SYSMO_L1_IF_H */