diff --git a/HamShield-Serial-Mode.md b/HamShield-Serial-Mode.md
index c4e8256..443f008 100644
--- a/HamShield-Serial-Mode.md
+++ b/HamShield-Serial-Mode.md
@@ -7,12 +7,11 @@ Commands are not echoed to the sender. Only status responses are provided back o
 HamShield Serial Interface Commands
 
 <table border=1>
-<tr>
- <td>Mode</td>
- <td>ASCII</td>
- <td>Description</td>
-</tr>
+<tr><td>Mode</td><td>ASCII</td><td>Description</td></tr>
 <tr><td>Transmit</td><td>[Spacebar]</td><td>Space must be received at least every 500 milliseconds</td></tr>
+<tr><td>Receive Mode</td><td>[None]</td><td>If nothing is received or the transmit times out after 500 ms, unit goes into receive mode</td></tr>
+<tr><td>CTCSS In</td><td>A[tone];</td><td>Tone must be numerical ASCII with decimal point indicating CTCSS receive tone required to unsquelch</td></tr>
+<tr><td>CTCSS Out</td><td>B[tone];</td><td>Tone must be numerical ASCII with decimal point indicating CTCSS transmit tone</td></tr>
 </table>