diff --git a/Makefile b/Makefile
index 796d2f0..8183fbb 100644
--- a/Makefile
+++ b/Makefile
@@ -2,15 +2,17 @@ CC		= gcc
 
 VERSION         = 0.7
 GITCOUNT        = $(shell git rev-list HEAD --count)
+UNAME           = $(shell uname)
 CFLAGS		= -g -O -Wall -Werror -DVERSION='"$(VERSION).$(GITCOUNT)"'
 LDFLAGS		= -g
 
 OBJS		= main.o util.o radio.o dfu-libusb.o uv380.o md380.o
 LIBS            = -lusb-1.0
 
-# Mac OS X
-#CFLAGS          += -I/usr/local/opt/gettext/include
-#LIBS            += -L/usr/local/opt/gettext/lib -lintl
+# Linux
+ifeq ($(UNAME),Linux)
+    OBJS        += hid-libusb.o
+endif
 
 all:		dmrconfig
 
diff --git a/dfu-libusb.c b/dfu-libusb.c
index b2fe9df..81ed570 100644
--- a/dfu-libusb.c
+++ b/dfu-libusb.c
@@ -291,11 +291,13 @@ const char *dfu_init(unsigned vid, unsigned pid)
 
     dev = libusb_open_device_with_vid_pid(ctx, vid, pid);
     if (!dev) {
-        fprintf(stderr, "Cannot find USB device %04x:%04x\n",
-            vid, pid);
+        if (trace_flag) {
+            fprintf(stderr, "Cannot find USB device %04x:%04x\n",
+                vid, pid);
+        }
         libusb_exit(ctx);
         ctx = 0;
-        exit(-1);
+        return 0;
     }
     if (libusb_kernel_driver_active(dev, 0)) {
         libusb_detach_kernel_driver(dev, 0);
diff --git a/hid-libusb.c b/hid-libusb.c
new file mode 100644
index 0000000..6e12448
--- /dev/null
+++ b/hid-libusb.c
@@ -0,0 +1,269 @@
+/*
+ * HID routines for Linux, via libusb-1.0.
+ *
+ * Copyright (C) 2018 Serge Vakulenko, KK6ABQ
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice,
+ *      this list of conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *   3. The name of the author may not be used to endorse or promote products
+ *      derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <libusb-1.0/libusb.h>
+#include "util.h"
+
+static libusb_context *ctx = NULL;          // libusb context
+static libusb_device_handle *dev;           // libusb device
+static unsigned char receive_buf[42];       // receive buffer
+static volatile int nbytes_received = 0;    // receive result
+
+#define HID_INTERFACE   0                   // interface index
+#define TIMEOUT_MSEC    500                 // receive timeout
+
+//
+// Callback function for asynchronous receive.
+// Needs to fill the receive_buf and set nbytes_received.
+//
+static void read_callback(struct libusb_transfer *transfer)
+{
+    switch (transfer->status) {
+    case LIBUSB_TRANSFER_COMPLETED:
+        //fprintf(stderr, "%s: Transfer complete, %d bytes\n", __func__, transfer->actual_length);
+        memcpy(receive_buf, transfer->buffer, transfer->actual_length);
+        nbytes_received = transfer->actual_length;
+        break;
+
+    case LIBUSB_TRANSFER_CANCELLED:
+        //fprintf(stderr, "%s: Transfer cancelled\n", __func__);
+        nbytes_received = LIBUSB_ERROR_INTERRUPTED;
+        return;
+
+    case LIBUSB_TRANSFER_NO_DEVICE:
+        //fprintf(stderr, "%s: No device\n", __func__);
+        nbytes_received = LIBUSB_ERROR_NO_DEVICE;
+        return;
+
+    case LIBUSB_TRANSFER_TIMED_OUT:
+        //fprintf(stderr, "%s: Timeout (normal)\n", __func__);
+        nbytes_received = LIBUSB_ERROR_TIMEOUT;
+        break;
+
+    default:
+        //fprintf(stderr, "%s: Unknown transfer code: %d\n", __func__, transfer->status);
+        nbytes_received = LIBUSB_ERROR_IO;
+   }
+}
+
+//
+// Write data to the device and receive reply.
+// Return negative status on error.
+// Return received byte count of success.
+// On timeout, repeat the transaction.
+// Need to use callback for receive interrupt transfer.
+//
+static int write_read(const unsigned char *data, unsigned length, unsigned char *reply, unsigned rlength)
+{
+    struct libusb_transfer *transfer = libusb_alloc_transfer(0);
+again:
+    nbytes_received = 0;
+    libusb_fill_interrupt_transfer(transfer, dev,
+        LIBUSB_RECIPIENT_INTERFACE|LIBUSB_ENDPOINT_IN,
+        reply, rlength, read_callback, 0, TIMEOUT_MSEC);
+    libusb_submit_transfer(transfer);
+
+    int result = libusb_control_transfer(dev,
+        LIBUSB_REQUEST_TYPE_CLASS|LIBUSB_RECIPIENT_INTERFACE|LIBUSB_ENDPOINT_OUT,
+        0x09/*HID Set_Report*/, (2/*HID output*/ << 8) | 0,
+        HID_INTERFACE, (unsigned char*)data, length, TIMEOUT_MSEC);
+
+    if (result < 0) {
+        fprintf(stderr, "Error %d transmitting data via control transfer: %s\n",
+            result, libusb_strerror(result));
+        libusb_cancel_transfer(transfer);
+        libusb_free_transfer(transfer);
+        return -1;
+    }
+
+    while (nbytes_received == 0) {
+        result = libusb_handle_events(ctx);
+        if (result < 0) {
+            /* Break out of this loop only on fatal error.*/
+            if (result != LIBUSB_ERROR_BUSY &&
+                result != LIBUSB_ERROR_TIMEOUT &&
+                result != LIBUSB_ERROR_OVERFLOW &&
+                result != LIBUSB_ERROR_INTERRUPTED) {
+                fprintf(stderr, "Error %d receiving data via interrupt transfer: %s\n",
+                    result, libusb_strerror(result));
+                libusb_free_transfer(transfer);
+                return result;
+            }
+        }
+    }
+
+    if (nbytes_received == LIBUSB_ERROR_TIMEOUT) {
+        //fprintf(stderr, "Timed out!\n");
+        goto again;
+    }
+    libusb_free_transfer(transfer);
+    return nbytes_received;
+}
+
+//
+// Send a request to the device.
+// Store the reply into the rdata[] array.
+// Terminate in case of errors.
+//
+void hid_send_recv(const unsigned char *data, unsigned nbytes, unsigned char *rdata, unsigned rlength)
+{
+    unsigned char buf[42];
+    unsigned char reply[42];
+    unsigned k;
+    int reply_len;
+
+    memset(buf, 0, sizeof(buf));
+    buf[0] = 1;
+    buf[1] = 0;
+    buf[2] = nbytes;
+    buf[3] = nbytes >> 8;
+    if (nbytes > 0)
+        memcpy(buf+4, data, nbytes);
+    nbytes += 4;
+
+    if (trace_flag > 0) {
+        fprintf(stderr, "---Send");
+        for (k=0; k<nbytes; ++k) {
+            if (k != 0 && (k & 15) == 0)
+                fprintf(stderr, "\n       ");
+            fprintf(stderr, " %02x", buf[k]);
+        }
+        fprintf(stderr, "\n");
+    }
+    reply_len = write_read(buf, sizeof(buf), reply, sizeof(reply));
+    if (reply_len < 0) {
+        exit(-1);
+    }
+    if (reply_len != sizeof(reply)) {
+        fprintf(stderr, "Short read: %d bytes instead of %d!\n",
+            reply_len, (int)sizeof(reply));
+        exit(-1);
+    }
+    if (trace_flag > 0) {
+        fprintf(stderr, "---Recv");
+        for (k=0; k<reply_len; ++k) {
+            if (k != 0 && (k & 15) == 0)
+                fprintf(stderr, "\n       ");
+            fprintf(stderr, " %02x", reply[k]);
+        }
+        fprintf(stderr, "\n");
+    }
+    if (reply[0] != 3 || reply[1] != 0 || reply[3] != 0) {
+        fprintf(stderr, "incorrect reply\n");
+        exit(-1);
+    }
+    if (reply[2] != rlength) {
+        fprintf(stderr, "incorrect reply length %d, expected %d\n",
+            reply[2], rlength);
+        exit(-1);
+    }
+    memcpy(rdata, reply+4, rlength);
+}
+
+//
+// Connect to the specified device.
+// Initiate the programming session.
+// Query and return the device identification string.
+//
+const char *hid_init(unsigned vid, unsigned pid)
+{
+    int error = libusb_init(&ctx);
+    if (error < 0) {
+        fprintf(stderr, "libusb init failed: %d: %s\n",
+            error, libusb_strerror(error));
+        exit(-1);
+    }
+
+    dev = libusb_open_device_with_vid_pid(ctx, vid, pid);
+    if (!dev) {
+        if (trace_flag) {
+            fprintf(stderr, "Cannot find USB device %04x:%04x\n",
+                vid, pid);
+        }
+        libusb_exit(ctx);
+        ctx = 0;
+        return 0;
+    }
+    if (libusb_kernel_driver_active(dev, 0)) {
+        libusb_detach_kernel_driver(dev, 0);
+    }
+
+    error = libusb_claim_interface(dev, HID_INTERFACE);
+    if (error < 0) {
+        fprintf(stderr, "Failed to claim USB interface: %d: %s\n",
+            error, libusb_strerror(error));
+        libusb_close(dev);
+        libusb_exit(ctx);
+        ctx = 0;
+        exit(-1);
+    }
+
+    static const unsigned char CMD_PRG[]  = "\2PROGRA";
+    static const unsigned char CMD_PRG2[] = "M\2";
+    static const unsigned char CMD_ACK    = 0x41;
+    static unsigned char reply[38];
+
+    hid_send_recv(CMD_PRG, 7, reply, 1);
+    if (reply[0] != CMD_ACK) {
+        fprintf(stderr, "Wrong reply %#x, expected %#x\n", reply[0], CMD_ACK);
+        return 0;
+    }
+
+    hid_send_recv(CMD_PRG2, 2, reply, 16);
+
+// ---Send 01 00 07 00 02 50 52 4f 47 52 41
+// ---Recv 03 00 01 00 41 00 00 00 00 00 00 00 00 00 00 00
+//         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+//         00 00 00 00 00 00 00 00 00 00
+// ---Send 01 00 02 00 4d 02
+// ---Recv 03 00 10 00 42 46 2d 35 52 ff ff ff 56 32 31 30
+//         00 04 80 04 00 00 00 00 00 00 00 00 00 00 00 00
+//         00 00 00 00 00 00 00 00 00 00
+
+// 42 46 2d 35 52 ff ff ff 56 32 31 30 00 04 80 04
+//  B  F  -  5  R           V  2  1  0
+
+    // Terminate the string.
+    char *p = memchr(reply, 0xff, sizeof(reply));
+    if (p)
+        *p = 0;
+    return (char*)reply;
+}
+
+void hid_close()
+{
+    if (ctx) {
+        libusb_release_interface(dev, HID_INTERFACE);
+        libusb_close(dev);
+        libusb_exit(ctx);
+        ctx = 0;
+    }
+}
diff --git a/radio.c b/radio.c
index 4c84e96..57fbf8d 100644
--- a/radio.c
+++ b/radio.c
@@ -80,10 +80,21 @@ void radio_print_version(FILE *out)
 //
 void radio_connect()
 {
-    // Only TYT MD family for now.
-    const char *ident = dfu_init(0x0483, 0xdf11);
+    const char *ident;
     int i;
 
+    // Try TYT MD family.
+    ident = dfu_init(0x0483, 0xdf11);
+    if (! ident) {
+        // Try RD-5R.
+        ident = hid_init(0x15a2, 0x0073);
+    }
+    if (! ident) {
+        fprintf(stderr, "No radio detected.\n");
+        fprintf(stderr, "Check your USB cable!\n");
+        exit(-1);
+    }
+
     for (i=0; radio_tab[i].ident; i++) {
         if (strcasecmp(ident, radio_tab[i].ident) == 0) {
             device = radio_tab[i].device;
diff --git a/util.h b/util.h
index 471f549..d2c6d0c 100644
--- a/util.h
+++ b/util.h
@@ -65,6 +65,13 @@ void dfu_read_block(int bno, unsigned char *data, int nbytes);
 void dfu_write_block(int bno, unsigned char *data, int nbytes);
 void dfu_reboot(void);
 
+//
+// HID functions.
+//
+const char *hid_init(unsigned vid, unsigned pid);
+void hid_close(void);
+int hid_write_read(const unsigned char *data, unsigned length, unsigned char *reply, unsigned rlength);
+
 //
 // Delay in milliseconds.
 //