diff --git a/include/patty/ax25/aprs_is.h b/include/patty/ax25/aprs_is.h
index 3b792d1..8695dfe 100644
--- a/include/patty/ax25/aprs_is.h
+++ b/include/patty/ax25/aprs_is.h
@@ -33,12 +33,6 @@ patty_ax25_aprs_is *patty_ax25_aprs_is_new(patty_ax25_aprs_is_info *info);
 
 void patty_ax25_aprs_is_destroy(patty_ax25_aprs_is *aprs);
 
-ssize_t patty_ax25_aprs_is_readline(patty_ax25_aprs_is *aprs,
-                                    void *buf,
-                                    size_t len);
-
-int patty_ax25_aprs_is_printf(patty_ax25_aprs_is *aprs, const char *fmt, ...);
-
 int patty_ax25_aprs_is_fd(patty_ax25_aprs_is *aprs);
 
 ssize_t patty_ax25_aprs_is_pending(patty_ax25_aprs_is *aprs);
diff --git a/src/aprs_is.c b/src/aprs_is.c
index b4636f1..69cabc5 100644
--- a/src/aprs_is.c
+++ b/src/aprs_is.c
@@ -41,51 +41,39 @@ struct _patty_ax25_aprs_is {
             encoded;
 };
 
-static ssize_t send_line(patty_ax25_aprs_is *aprs, char *buf, size_t len) {
-    if (len > PATTY_AX25_APRS_IS_PACKET_MAX - 2) {
-        len = PATTY_AX25_APRS_IS_PACKET_MAX - 2;
-    }
+static ssize_t aprs_is_vprintf(patty_ax25_aprs_is *aprs,
+                               const char *fmt,
+                               va_list args) {
+    int len;
 
-    buf[len]   = '\r';
-    buf[len+1] = '\n';
-
-    return write(aprs->fd, buf, len+2);
-}
-
-static int send_va(patty_ax25_aprs_is *aprs, const char *fmt, va_list args) {
-    size_t len;
-
-    if (vsnprintf(aprs->tx_buf, PATTY_AX25_APRS_IS_PACKET_MAX, fmt, args) < 0) {
+    if ((len = vsnprintf(aprs->tx_buf,
+                         PATTY_AX25_APRS_IS_PACKET_MAX,
+                         fmt,
+                         args)) < 0) {
         goto error_vsnprintf;
     }
 
-    len = strnlen(aprs->tx_buf, PATTY_AX25_APRS_IS_PACKET_MAX);
+    return write(aprs->fd, aprs->tx_buf, (size_t)len);
 
-    if (send_line(aprs, aprs->tx_buf, len) < 0) {
-        goto error_send_line;
-    }
-
-    return 0;
-
-error_send_line:
 error_vsnprintf:
     return -1;
 }
 
-static int send_fmt(patty_ax25_aprs_is *aprs, const char *fmt, ...) {
+static ssize_t aprs_is_printf(patty_ax25_aprs_is *aprs, const char *fmt, ...) {
+    ssize_t len;
     va_list args;
 
     va_start(args, fmt);
 
-    if (send_va(aprs, fmt, args) < 0) {
-        goto error_send_va;
+    if ((len = aprs_is_vprintf(aprs, fmt, args)) < 0) {
+        goto error_aprs_is_vprintf;
     }
 
     va_end(args);
 
-    return 0;
+    return len;
 
-error_send_va:
+error_aprs_is_vprintf:
     return -1;
 }
 
@@ -113,20 +101,20 @@ static int aprs_is_connect(patty_ax25_aprs_is *aprs,
 
         freeaddrinfo(ai0);
 
-        if (send_fmt(aprs,
-                     "user %s pass %s vers %s %s filter %s",
-                     info->user,
-                     info->pass,
-                     info->appname,
-                     info->version,
-                     info->filter) < 0) {
-            goto error_send_fmt;
+        if (aprs_is_printf(aprs,
+                           "user %s pass %s vers %s %s filter %s\r\n",
+                           info->user,
+                           info->pass,
+                           info->appname,
+                           info->version,
+                           info->filter) < 0) {
+            goto error_aprs_is_printf;
         }
 
         return 0;
     }
 
-error_send_fmt:
+error_aprs_is_printf:
     close(aprs->fd);
 
 error_getaddrinfo:
@@ -322,29 +310,97 @@ ssize_t patty_ax25_aprs_is_flush(patty_ax25_aprs_is *aprs) {
     return ret;
 }
 
-int patty_ax25_aprs_is_printf(patty_ax25_aprs_is *aprs, const char *fmt, ...) {
-    va_list args;
-
-    va_start(args, fmt);
-
-    if (send_va(aprs, fmt, args) < 0) {
-        goto error_send_va;
-    }
-
-    va_end(args);
-
-    return 0;
-
-error_send_va:
-    va_end(args);
-
-    return -1;
-}
-
 ssize_t patty_ax25_aprs_is_send(patty_ax25_aprs_is *aprs,
                                 const void *buf,
                                 size_t len) {
-    return 0;
+    patty_ax25_frame frame;
+
+    size_t offset = 0;
+    ssize_t decoded;
+
+    int formatted,
+        i;
+
+    char station[PATTY_AX25_ADDRSTRLEN+1];
+
+    if ((decoded = patty_ax25_frame_decode_address(&frame, buf, len)) < 0) {
+        goto error;
+    }
+
+    if (patty_ax25_frame_decode_control(&frame,
+                                        PATTY_AX25_FRAME_NORMAL,
+                                        buf,
+                                        decoded,
+                                        len) < 0) {
+        goto error;
+    }
+
+    if (!PATTY_AX25_FRAME_CONTROL_UI(frame.control)) {
+        return 0;
+    }
+
+    if (patty_ax25_ntop(&frame.src, station, sizeof(station)) < 0) {
+        goto error;
+    }
+
+    if ((formatted = snprintf(aprs->tx_buf,
+                              aprs->tx_bufsz,
+                              "%s>",
+                              station)) < 0) {
+        goto error;
+    } else {
+        offset += formatted;
+    }
+
+    if (patty_ax25_ntop(&frame.dest, station, sizeof(station)) < 0) {
+        goto error;
+    }
+
+    if ((formatted = snprintf(aprs->tx_buf + offset,
+                              aprs->tx_bufsz - offset,
+                              "%s",
+                              station)) < 0) {
+        goto error;
+    } else {
+        offset += formatted;
+    }
+
+    for (i=0; i<frame.hops; i++) {
+        if (patty_ax25_ntop(&frame.repeaters[i],
+                            station,
+                            sizeof(station)) < 0) {
+            goto error;
+        }
+
+        if ((formatted = snprintf(aprs->tx_buf + offset,
+                                  aprs->tx_bufsz - offset,
+                                  ",%s",
+                                  station)) < 0) {
+            goto error;
+        } else {
+            offset += formatted;
+        }
+    }
+
+    if (aprs->tx_bufsz - offset < frame.infolen + 3) {
+        errno = EOVERFLOW;
+
+        goto error;
+    }
+
+    aprs->tx_buf[offset++] = ':';
+
+    memcpy(aprs->tx_buf + offset, frame.info, frame.infolen);
+
+    offset += frame.infolen;
+
+    aprs->tx_buf[offset++] = '\r';
+    aprs->tx_buf[offset++] = '\n';
+
+    return write(aprs->fd, aprs->tx_buf, offset);
+
+error:
+    return -1;
 }
 
 patty_ax25_if_driver *patty_ax25_aprs_is_driver() {