diff --git a/nimble/controller/include/controller/ble_ll.h b/nimble/controller/include/controller/ble_ll.h
index 6d5dac950..5fe808410 100644
--- a/nimble/controller/include/controller/ble_ll.h
+++ b/nimble/controller/include/controller/ble_ll.h
@@ -567,7 +567,7 @@ extern uint32_t g_bletest_IVm;
 extern uint32_t g_bletest_IVs;
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 void ble_ll_dtm_init(void);
 #endif
 
diff --git a/nimble/controller/include/controller/ble_ll_sched.h b/nimble/controller/include/controller/ble_ll_sched.h
index 39955eb0b..4ad306ddc 100644
--- a/nimble/controller/include/controller/ble_ll_sched.h
+++ b/nimble/controller/include/controller/ble_ll_sched.h
@@ -214,7 +214,7 @@ void ble_ll_sched_stop(void);
 void ble_ll_sched_rfclk_chk_restart(void);
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 int ble_ll_sched_dtm(struct ble_ll_sched_item *sch);
 #endif
 
diff --git a/nimble/controller/include/controller/ble_phy.h b/nimble/controller/include/controller/ble_phy.h
index 463816250..dd5250cef 100644
--- a/nimble/controller/include/controller/ble_phy.h
+++ b/nimble/controller/include/controller/ble_phy.h
@@ -243,7 +243,7 @@ static inline int ble_ll_phy_to_phy_mode(int phy, int phy_options)
     return phy_mode;
 }
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 void ble_phy_enable_dtm(void);
 void ble_phy_disable_dtm(void);
 #endif
diff --git a/nimble/controller/src/ble_ll.c b/nimble/controller/src/ble_ll.c
index 79921758f..36c7619cb 100644
--- a/nimble/controller/src/ble_ll.c
+++ b/nimble/controller/src/ble_ll.c
@@ -45,7 +45,7 @@
 #include "controller/ble_ll_sync.h"
 #include "ble_ll_conn_priv.h"
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 #include "ble_ll_dtm_priv.h"
 #endif
 
@@ -617,7 +617,7 @@ ble_ll_wfr_timer_exp(void *arg)
         case BLE_LL_STATE_INITIATING:
             ble_ll_conn_init_wfr_timer_exp();
             break;
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
         case BLE_LL_STATE_DTM:
             ble_ll_dtm_wfr_timer_exp();
             break;
@@ -717,7 +717,7 @@ ble_ll_count_rx_stats(struct ble_mbuf_hdr *hdr, uint16_t len, uint8_t pdu_type)
     crcok = BLE_MBUF_HDR_CRC_OK(hdr);
     connection_data = (BLE_MBUF_HDR_RX_STATE(hdr) == BLE_LL_STATE_CONNECTION);
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     /* Reuse connection stats for DTM */
     connection_data = (BLE_MBUF_HDR_RX_STATE(hdr) == BLE_LL_STATE_DTM);
 #endif
@@ -794,7 +794,7 @@ ble_ll_rx_pkt_in(void)
         case BLE_LL_STATE_INITIATING:
             ble_ll_init_rx_pkt_in(pdu_type, rxbuf, ble_hdr);
             break;
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
         case BLE_LL_STATE_DTM:
             ble_ll_dtm_rx_pkt_in(m, ble_hdr);
             break;
@@ -930,7 +930,7 @@ ble_ll_rx_start(uint8_t *rxbuf, uint8_t chan, struct ble_mbuf_hdr *rxhdr)
     case BLE_LL_STATE_SCANNING:
         rc = ble_ll_scan_rx_isr_start(pdu_type, &rxhdr->rxinfo.flags);
         break;
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     case BLE_LL_STATE_DTM:
         rc = ble_ll_dtm_rx_isr_start(rxhdr, ble_phy_access_addr_get());
         break;
@@ -983,7 +983,7 @@ ble_ll_rx_end(uint8_t *rxbuf, struct ble_mbuf_hdr *rxhdr)
     ble_ll_trace_u32x3(BLE_LL_TRACE_ID_RX_END, pdu_type, len,
                        rxhdr->rxinfo.flags);
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     if (BLE_MBUF_HDR_RX_STATE(rxhdr) == BLE_LL_STATE_DTM) {
         rc = ble_ll_dtm_rx_isr_end(rxbuf, rxhdr);
         return rc;
@@ -1318,7 +1318,7 @@ ble_ll_reset(void)
     /* Stop any advertising */
     ble_ll_adv_reset();
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     ble_ll_dtm_reset();
 #endif
 
@@ -1628,7 +1628,7 @@ ble_ll_init(void)
                             "ble_ll");
     SYSINIT_PANIC_ASSERT(rc == 0);
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     ble_ll_dtm_init();
 #endif
 
diff --git a/nimble/controller/src/ble_ll_dtm.c b/nimble/controller/src/ble_ll_dtm.c
index 4a92d8efa..0599aab6d 100644
--- a/nimble/controller/src/ble_ll_dtm.c
+++ b/nimble/controller/src/ble_ll_dtm.c
@@ -49,6 +49,9 @@ struct dtm_ctx {
     uint8_t itvl_rem_usec;
     uint16_t num_of_packets;
     uint32_t itvl_ticks;
+#if MYNEWT_VAL(BLE_DTM_CLI_EXTENSIONS_ENABLE)
+    uint16_t num_of_packets_max;
+#endif
     int active;
     uint8_t rf_channel;
     uint8_t phy_mode;
@@ -140,6 +143,8 @@ static const uint8_t channel_rf_to_index[] = {
 #define BLE_DTM_SYNC_WORD          (0x71764129)
 #define BLE_DTM_CRC                (0x555555)
 
+static void ble_ll_dtm_ctx_free(struct dtm_ctx * ctx);
+
 static void
 ble_ll_dtm_set_next(struct dtm_ctx *ctx)
 {
@@ -169,6 +174,18 @@ ble_ll_dtm_ev_tx_resched_cb(struct ble_npl_event *evt) {
     }
     OS_EXIT_CRITICAL(sr);
 
+#if MYNEWT_VAL(BLE_DTM_CLI_EXTENSIONS_ENABLE)
+    if (g_ble_ll_dtm_ctx.num_of_packets_max &&
+        (g_ble_ll_dtm_ctx.num_of_packets == g_ble_ll_dtm_ctx.num_of_packets_max)) {
+        /*
+         * XXX do not send more packets, but also do not stop DTM - it shall be
+         * stopped as usual by HCI command since there is no standard way to
+         * signal end of test to host.
+         */
+        return;
+    }
+#endif
+
     ble_ll_dtm_set_next(ctx);
     rc = ble_ll_sched_dtm(&ctx->sch);
     BLE_LL_ASSERT(rc == 0);
@@ -194,6 +211,8 @@ ble_ll_dtm_tx_done(void *arg)
         return;
     }
 
+    g_ble_ll_dtm_ctx.num_of_packets++;
+
     /* Reschedule event in LL context */
     ble_npl_eventq_put(&g_ble_ll_data.ll_evq, &ctx->evt);
 
@@ -249,7 +268,8 @@ resched:
 }
 
 static void
-ble_ll_dtm_calculate_itvl(struct dtm_ctx *ctx, uint8_t len, int phy_mode)
+ble_ll_dtm_calculate_itvl(struct dtm_ctx *ctx, uint8_t len,
+                          uint16_t cmd_interval, int phy_mode)
 {
     uint32_t l;
     uint32_t itvl_usec;
@@ -259,6 +279,12 @@ ble_ll_dtm_calculate_itvl(struct dtm_ctx *ctx, uint8_t len, int phy_mode)
     l = ble_ll_pdu_tx_time_get(len + BLE_LL_PDU_HDR_LEN, phy_mode);
     itvl_usec = ((l + 249 + 624) / 625) * 625;
 
+#if MYNEWT_VAL(BLE_LL_DTM_EXTENSIONS_ENABLE)
+    if (cmd_interval > itvl_usec) {
+        itvl_usec = cmd_interval;
+    }
+#endif
+
     itvl_ticks = os_cputime_usecs_to_ticks(itvl_usec);
     ctx->itvl_rem_usec = (itvl_usec - os_cputime_ticks_to_usecs(itvl_ticks));
     if (ctx->itvl_rem_usec == 31) {
@@ -270,7 +296,8 @@ ble_ll_dtm_calculate_itvl(struct dtm_ctx *ctx, uint8_t len, int phy_mode)
 
 static int
 ble_ll_dtm_tx_create_ctx(uint8_t packet_payload, uint8_t len,
-                         uint8_t rf_channel, uint8_t phy_mode)
+                         uint8_t rf_channel, uint8_t phy_mode,
+                         uint16_t cmd_interval, uint16_t cmd_pkt_count)
 {
     int rc = 0;
     uint8_t byte_pattern;
@@ -285,6 +312,10 @@ ble_ll_dtm_tx_create_ctx(uint8_t packet_payload, uint8_t len,
 
     g_ble_ll_dtm_ctx.phy_mode = phy_mode;
     g_ble_ll_dtm_ctx.rf_channel = rf_channel;
+    g_ble_ll_dtm_ctx.num_of_packets = 0;
+#if MYNEWT_VAL(BLE_DTM_CLI_EXTENSIONS_ENABLE)
+    g_ble_ll_dtm_ctx.num_of_packets_max = cmd_pkt_count;
+#endif
 
     /* Set BLE transmit header */
     ble_hdr = BLE_MBUF_HDR_PTR(m);
@@ -344,7 +375,7 @@ schedule:
     ble_npl_event_init(&g_ble_ll_dtm_ctx.evt, ble_ll_dtm_ev_tx_resched_cb,
                        &g_ble_ll_dtm_ctx);
 
-    ble_ll_dtm_calculate_itvl(&g_ble_ll_dtm_ctx, len, phy_mode);
+    ble_ll_dtm_calculate_itvl(&g_ble_ll_dtm_ctx, len, cmd_interval, phy_mode);
 
     /* Set some start point for TX packets */
     rc = ble_ll_sched_dtm(sch);
@@ -440,17 +471,28 @@ ble_ll_dtm_ctx_free(struct dtm_ctx * ctx)
 }
 
 int
-ble_ll_dtm_tx_test(uint8_t *cmdbuf, bool enhanced)
+ble_ll_dtm_tx_test(uint8_t *cmdbuf, uint8_t cmdlen, bool enhanced)
 {
+    uint8_t cmdlen_valid;
     uint8_t tx_chan = cmdbuf[0];
     uint8_t len = cmdbuf[1];
     uint8_t packet_payload = cmdbuf[2];
     uint8_t phy_mode = BLE_PHY_MODE_1M;
+    uint16_t interval = 0;
+    uint16_t pkt_count = 0;
 
     if (g_ble_ll_dtm_ctx.active) {
         return BLE_ERR_CTLR_BUSY;
     }
 
+    cmdlen_valid = enhanced ? BLE_HCI_LE_ENH_TX_TEST_LEN : BLE_HCI_TX_TEST_LEN;
+
+#if !MYNEWT_VAL(BLE_LL_DTM_EXTENSIONS_ENABLE)
+    if (cmdlen != cmdlen_valid) {
+        return BLE_ERR_INV_HCI_CMD_PARMS;
+    }
+#endif
+
     if (enhanced) {
         switch (cmdbuf[3]) {
         case BLE_HCI_LE_PHY_1M:
@@ -478,7 +520,17 @@ ble_ll_dtm_tx_test(uint8_t *cmdbuf, bool enhanced)
         return BLE_ERR_INV_HCI_CMD_PARMS;
     }
 
-    if (ble_ll_dtm_tx_create_ctx(packet_payload, len, tx_chan, phy_mode)) {
+#if MYNEWT_VAL(BLE_LL_DTM_EXTENSIONS_ENABLE)
+    if (cmdlen == cmdlen_valid + 4) {
+        interval = get_le16(cmdbuf + cmdlen_valid );
+        pkt_count = get_le16(cmdbuf + cmdlen_valid  + 2);
+    } else if (cmdlen != cmdlen_valid) {
+        return BLE_ERR_INV_HCI_CMD_PARMS;
+    }
+#endif
+
+    if (ble_ll_dtm_tx_create_ctx(packet_payload, len, tx_chan, phy_mode,
+                                 interval, pkt_count)) {
         return BLE_ERR_UNSPECIFIED;
     }
 
diff --git a/nimble/controller/src/ble_ll_dtm_priv.h b/nimble/controller/src/ble_ll_dtm_priv.h
index 5341cd28d..d6633f158 100644
--- a/nimble/controller/src/ble_ll_dtm_priv.h
+++ b/nimble/controller/src/ble_ll_dtm_priv.h
@@ -24,7 +24,7 @@
 #include <stdbool.h>
 #include "nimble/ble.h"
 
-int ble_ll_dtm_tx_test(uint8_t *cmdbuf, bool enhanced);
+int ble_ll_dtm_tx_test(uint8_t *cmdbuf, uint8_t cmdlen, bool enhanced);
 int ble_ll_dtm_rx_test(uint8_t *cmdbuf, bool enhanced);
 int ble_ll_dtm_end_test(uint8_t *rsp, uint8_t *rsplen);
 
diff --git a/nimble/controller/src/ble_ll_hci.c b/nimble/controller/src/ble_ll_hci.c
index c809a5ac5..817d8631c 100644
--- a/nimble/controller/src/ble_ll_hci.c
+++ b/nimble/controller/src/ble_ll_hci.c
@@ -38,7 +38,7 @@
 #include "hal/hal_gpio.h"
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 #include "ble_ll_dtm_priv.h"
 #endif
 
@@ -982,9 +982,7 @@ ble_ll_hci_le_cmd_proc(uint8_t *cmdbuf, uint16_t ocf, uint8_t *rsplen,
         break;
 #if MYNEWT_VAL(BLE_LL_DTM)
     case BLE_HCI_OCF_LE_TX_TEST:
-        if (len == BLE_HCI_TX_TEST_LEN) {
-            rc = ble_ll_dtm_tx_test(cmdbuf, false);
-        }
+        rc = ble_ll_dtm_tx_test(cmdbuf, len, false);
         break;
     case BLE_HCI_OCF_LE_RX_TEST:
         if (len == BLE_HCI_RX_TEST_LEN) {
@@ -1090,16 +1088,14 @@ ble_ll_hci_le_cmd_proc(uint8_t *cmdbuf, uint16_t ocf, uint8_t *rsplen,
         }
         break;
 #endif
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
     case BLE_HCI_OCF_LE_ENH_RX_TEST:
         if (len == BLE_HCI_LE_ENH_RX_TEST_LEN) {
             rc = ble_ll_dtm_rx_test(cmdbuf, true);
         }
         break;
     case BLE_HCI_OCF_LE_ENH_TX_TEST:
-        if (len == BLE_HCI_LE_ENH_TX_TEST_LEN) {
-            rc = ble_ll_dtm_tx_test(cmdbuf, true);
-        }
+        rc = ble_ll_dtm_tx_test(cmdbuf, len, true);
         break;
 #endif
 #if MYNEWT_VAL(BLE_LL_CFG_FEAT_LL_EXT_ADV)
diff --git a/nimble/controller/src/ble_ll_sched.c b/nimble/controller/src/ble_ll_sched.c
index fa9b013f3..29742c277 100644
--- a/nimble/controller/src/ble_ll_sched.c
+++ b/nimble/controller/src/ble_ll_sched.c
@@ -1793,7 +1793,7 @@ done:
 }
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 int ble_ll_sched_dtm(struct ble_ll_sched_item *sch)
 {
     int rc;
diff --git a/nimble/controller/src/ble_ll_supp_cmd.c b/nimble/controller/src/ble_ll_supp_cmd.c
index 74ad601cc..8f62ed30b 100644
--- a/nimble/controller/src/ble_ll_supp_cmd.c
+++ b/nimble/controller/src/ble_ll_supp_cmd.c
@@ -137,7 +137,7 @@
 #endif
 #define BLE_SUPP_CMD_LE_READ_SUPP_STATES    (1 << 3)
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 #define BLE_SUPP_CMD_LE_RX_TEST             (1 << 4)
 #define BLE_SUPP_CMD_LE_TX_TEST             (1 << 5)
 #define BLE_SUPP_CMD_LE_TEST_END            (1 << 6)
@@ -233,7 +233,7 @@
 #define BLE_SUPP_CMD_LE_SET_PHY             (0 << 6)
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 #define BLE_SUPP_CMD_LE_ENHANCED_RX_TEST    (1 << 7)
 #else
 #define BLE_SUPP_CMD_LE_ENHANCED_RX_TEST    (0 << 7)
@@ -252,7 +252,7 @@
 )
 
 /* Octet 36 */
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 #define BLE_SUPP_CMD_LE_ENHANCED_TX_TEST    (1 << 0)
 #else
 #define BLE_SUPP_CMD_LE_ENHANCED_TX_TEST    (0 << 0)
diff --git a/nimble/controller/syscfg.yml b/nimble/controller/syscfg.yml
index 91b4bdc8a..e3c6b76ca 100644
--- a/nimble/controller/syscfg.yml
+++ b/nimble/controller/syscfg.yml
@@ -296,6 +296,24 @@ syscfg.defs:
         description: >
              Enables HCI Test commands needed for Bluetooth SIG certification
         value: MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+    BLE_LL_DTM_EXTENSIONS_ENABLE:
+        description: >
+             Enables non-standard extensions to HCI test commands. Once enabled,
+             HCI_LE_Transmitter_Test accepts extra parameters in addition to
+             those defined in Core specification
+               interval (2 octets)   interval between packets (usecs), overrides
+                                     standard interval
+               pkt_count (2 octets)  number of packets to transmit, controller
+                                     will automatically stop sending packets
+                                     after given number of packets was sent
+             Setting either of these parameters to 0 will configure for default
+             behavior, as per Core specification.
+             If specified interval is shorter then allowed by specification it
+             will be ignored.
+             Extended parameters shall immediately follow standard parameters.
+             Controller can accept both standard and extended version of command
+             depending on specified HCI command length.
+        value: 0
 
     BLE_LL_VND_EVENT_ON_ASSERT:
         description: >
diff --git a/nimble/drivers/nrf52/src/ble_phy.c b/nimble/drivers/nrf52/src/ble_phy.c
index a08ca883f..3b62660a1 100644
--- a/nimble/drivers/nrf52/src/ble_phy.c
+++ b/nimble/drivers/nrf52/src/ble_phy.c
@@ -2061,7 +2061,7 @@ ble_phy_resolv_list_disable(void)
 }
 #endif
 
-#if MYNEWT_VAL(BLE_LL_DIRECT_TEST_MODE)
+#if MYNEWT_VAL(BLE_LL_DTM)
 void ble_phy_enable_dtm(void)
 {
     /* When DTM is enabled we need to disable whitening as per
diff --git a/porting/npl/riot/include/syscfg/syscfg.h b/porting/npl/riot/include/syscfg/syscfg.h
index 8fb670067..4fde49794 100644
--- a/porting/npl/riot/include/syscfg/syscfg.h
+++ b/porting/npl/riot/include/syscfg/syscfg.h
@@ -517,8 +517,8 @@
 #define MYNEWT_VAL_BLE_LL_DBG_HCI_EV_PIN (-1)
 #endif
 
-#ifndef MYNEWT_VAL_BLE_LL_DIRECT_TEST_MODE
-#define MYNEWT_VAL_BLE_LL_DIRECT_TEST_MODE (0)
+#ifndef MYNEWT_VAL_BLE_LL_DTM
+#define MYNEWT_VAL_BLE_LL_DTM (0)
 #endif
 
 /* Overridden by nimble/controller (defined by nimble/controller) */