diff --git a/src/server.c b/src/server.c
index 7da6c33..a0f8892 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1242,6 +1242,8 @@ static int frame_ack(patty_ax25_server *server,
                      patty_ax25_frame *frame) {
     sock->rx_pending = 0;
 
+    patty_timer_start(&sock->timer_t3);
+
     if (patty_ax25_sock_ack(sock, frame->nr) > 0) {
         /*
          * AX.25 v2.2, Section 6.4.6 "Receiving Acknowledgement"
@@ -1255,6 +1257,10 @@ static int frame_ack(patty_ax25_server *server,
          * acknowledged, Timer T1 is started again.
          */
         patty_timer_stop(&sock->timer_t1);
+
+        if (patty_ax25_sock_ack_pending(sock) > 0) {
+            patty_timer_start(&sock->timer_t1);
+        }
     }
 
     if (PATTY_AX25_FRAME_CONTROL_S(frame->control) && frame->pf) {
@@ -1266,6 +1272,9 @@ static int frame_ack(patty_ax25_server *server,
          * to the last N(S) sent plus one, the TNC restarts Timer T1 and sets
          * its send state variable V(S) to the received N(R).  It may then
          * resume with I frame transmission or retransmission, as appropriate.
+         *
+         * Errata: It is not necessary, strictly speaking, to start Timer T1
+         * until the moment there are I frames ready to be sent to the peer.
          */
         int min = sock->va,
             max = sock->vs;
@@ -1277,8 +1286,6 @@ static int frame_ack(patty_ax25_server *server,
         if (frame->nr >= min && frame->nr <= max) {
             sock->vs      = frame->nr;
             sock->retries = sock->n_retry;
-
-            patty_timer_start(&sock->timer_t1);
         }
     }