diff --git a/include/osmocom/gsm/protocol/gsm_04_14.h b/include/osmocom/gsm/protocol/gsm_04_14.h
new file mode 100644
index 0000000..421b56f
--- /dev/null
+++ b/include/osmocom/gsm/protocol/gsm_04_14.h
@@ -0,0 +1,101 @@
+#pragma once
+
+#include <stdint.h>
+#include <osmocom/core/endian.h>
+#include <osmocom/core/utils.h>
+
+/* According to 3GPP TS 44.014 / GSM TS 04.14 */
+
+#define GSM414_MT_CLOSE_TCH_LOOP_CMD	0x00	/* 8.1 */
+enum gsm414_tch_loop_mode {
+	GSM414_LOOP_A	= 0x00,
+	GSM414_LOOP_B	= 0x01,
+	GSM414_LOOP_C	= 0x02,
+	GSM414_LOOP_D	= 0x04,
+	GSM414_LOOP_E	= 0x08,
+	GSM414_LOOP_F	= 0x0c,
+	GSM414_LOOP_I	= 0x1c,
+};
+
+#define GSM414_MT_CLOSE_TCH_LOOP_ACK	0x01	/* 8.2 */
+#define GSM414_MT_OPEN_LOOP_CMD		0x02	/* 8.3 */
+#define GSM414_OPEN_LOOP_ACK_IE		0x81
+
+#define GSM414_MT_CLOSE_MSLOT_LOOP_CMD	0x20	/* 8.4 */
+struct gsm414_close_mslot_loop_cmd {
+#if OSMO_IS_LITTLE_ENDIAN == 1
+	uint8_t chc:2,
+		loop_mech:3,
+		tn:3;
+#else
+	uint8_t tn:3,
+		loop_mech:3,
+		chc:2;
+#endif
+} __attribute__((packed));
+
+#define GSM414_MT_CLOSE_MSLOT_LOOP_ACK	0x21	/* 8.5 */
+struct gsm414_close_mslot_loop_ack {
+#if OSMO_IS_LITTLE_ENDIAN == 1
+	uint8_t err_ind:1,
+		loop_mech:3,
+		chc:2,
+		spare:2;
+#else
+	uint8_t spare:2,
+		chc:2,
+		loop_mech:3,
+		err_ind:1;
+#endif
+} __attribute__((packed));
+
+#define GSM414_MT_OPEN_MSLOT_LOOP_CMD	0x22	/* 8.6 */
+#define GSM414_MT_OPEN_MSLOT_LOOP_ACK	0x23	/* 8.7 */
+#define GSM414_MT_ACT_EMMI_CMD		0x0c	/* 8.8 */
+#define GSM414_MT_ACT_EMMI_ACK		0x0d	/* 8.9 */
+#define GSM414_MT_DEACT_EMMI_CMD	0x80	/* 8.10 */
+#define GSM414_MT_TEST_INTERFACE	0x84	/* 8.11 */
+
+/* 8.12 Timers (milli-seconds) */
+#define GSM414_TT01_MS	2500
+#define GSM414_TT02_MS	2500
+#define GSM414_TT03_MS	50
+
+#define GSM414_MT_GPRS_TEST_MODE_CMD	0x24	/* 8.13 */
+struct gsm414_gprs_test_mode_cmd {
+#if OSMO_IS_LITTLE_ENDIAN == 1
+	uint16_t d:12,
+		spare:3,
+		l:1;
+	uint8_t m:1,
+		dl_tx_offset:3,
+		_spare:4;
+#else
+	uint16_t l:1,
+		spare:3,
+		d:12;
+	uint8_t _spare:4,
+		dl_tx_offset:3,
+		m:1;
+#endif
+} __attribute__((packed));
+
+
+#define GSM414_MT_EGPRS_ST_RB_LOOP_CMD	0x25	/* 8.14 */
+struct gsm414_egprs_st_sb_loop_cmd {
+#if OSMO_IS_LITTLE_ENDIAN == 1
+	uint8_t _spare:4,
+		dl_tx_offset:3,
+		m:1;
+#else
+	uint8_t m:1,
+		dl_tx_offset:3,
+		_spare:4;
+#endif
+} __attribute__((packed));
+
+#define GSM414_MT_RESET_MS_POS_STORED	0x26	/* 8.15 */
+#define GSM414_MS_POS_TECH_AGPS		0x00
+#define GSM414_MS_POS_TECH_AGNSS	0x01
+
+extern const struct value_string gsm414_msgt_names[];