diff --git a/README.md b/README.md
index df0c014..e7d74bc 100644
--- a/README.md
+++ b/README.md
@@ -28,12 +28,12 @@ a 9V supply rail.
 
 The other pin mappings are as follows:
 
-| PET pin        | ESP pin | Direction | Cassette #1 internal | Cassette #2 internal |
-|----------------|---------|-----------|----------------------|----------------------|
-| Cassette Write | RXD     | PET->ESP  | VIA PB3              | VIA PB3 (same as #1) |
-| Cassette Read  | TXD     | ESP->PET  | PIA1 CA1             | VIA CB1              |
-| Cassette Motor | CTS     | PET->ESP  | PIA1 CB2             | VIA PB4              |
-| Cassette Sense | RTS     | ESP->PET  | PIA1 PA4             | PIA1 PA5             |
+| PET pin        | ESP pin | Direction | Cassette 1 external | Cassette 2 internal  |
+|----------------|---------|-----------|---------------------|----------------------|
+| Cassette Write | RXD     | PET->ESP  | VIA PB3             | VIA PB3 (same as #1) |
+| Cassette Read  | TXD     | ESP->PET  | PIA1 CA1            | VIA CB1              |
+| Cassette Motor | CTS     | PET->ESP  | PIA1 CB2            | VIA PB4              |
+| Cassette Sense | RTS     | ESP->PET  | PIA1 PA4            | PIA1 PA5             |
 
 A suitable serial signal (RS-232-like) must be generated/decoded in software.
 Make sure that you don't access the cassette port #1 while the adapter is
@@ -51,6 +51,7 @@ http://www.6502.org/users/andre/petindex/local/pet-io-2.txt
 | Start | +3V |     |
 | End   |     | -3V |
 
+```
    _   ___   ___     ____
 H   | |   | |   |   |
     | |   | |   |   |
@@ -62,6 +63,7 @@ L   |_|   |_|   |___|
     | |   | |   |   |
 -3 _| |___| |___|   |____
      S 1 1 0 1 1 0 0 1 E
+```
 
 ## PET RS232 Driver