diff --git a/PDP11/pdp11_ch.c b/PDP11/pdp11_ch.c
index f2d97394..e7dfaf1d 100644
--- a/PDP11/pdp11_ch.c
+++ b/PDP11/pdp11_ch.c
@@ -186,13 +186,18 @@ t_stat ch_rx_word (int32 *data)
     sim_debug (DBG_DAT, &ch_dev, "Read buffer word %d: %06o\n",
                rx_count, *data);
     rx_count--;
+    if (rx_count == 0) {
+      ch_lines[0].rcve = TRUE;
+      sim_debug (DBG_TRC, &ch_dev, "Read all, rx on\n");
+      status &= ~RXD;
+    }
   }
   return SCPE_OK;
 }
 
 t_stat ch_tx_word (int data)
 {
-  if (tx_count < 126) {
+  if (tx_count < 246) {
     int i = CHUDP_HEADER + 2*tx_count;
     sim_debug (DBG_DAT, &ch_dev, "Write buffer word %d: %06o\n",
                tx_count, data);
@@ -237,10 +242,11 @@ t_stat ch_transmit ()
   if (r == SCPE_OK) {
     sim_debug (DBG_PKT, &ch_dev, "Sent UDP packet, %d bytes.\n", (int)len);
     tmxr_poll_tx (&ch_tmxr);
-    status |= TXD;
-    ch_test_int ();
   } else
     sim_debug (DBG_ERR, &ch_dev, "Sending UDP failed: %d.\n", r);
+  tx_count = 0;
+  status |= TXD;
+  ch_test_int ();
   return SCPE_OK;
 }
 
@@ -405,7 +411,8 @@ t_stat ch_wr (int32 data, int32 PA, int32 access)
 t_stat ch_svc(UNIT *uptr)
 {
   sim_clock_coschedule (uptr, 1000);
-  (void)tmxr_poll_conn (&ch_tmxr);
+  if (tmxr_poll_conn (&ch_tmxr) != -1)
+    ch_lines[0].rcve = TRUE;
   if (ch_lines[0].conn)
     ch_receive ();
   return SCPE_OK;