Adding an optional RS-232 interface.

Using DTE card.

Wired to D6, D7, +3.3V, Ground on QTPy49-01 or QTPy49 card.

Pinout for J4 on QTPy49 cards:

1. GND
2. 3.3V
3. TX, D6
4. RX, D7

Tx on QTPy cards to Rx on DTE card.

Loopback on RTS/CTS lines on the DTE card satisfies hardware Handshakes.

Setup in MMBASIC

OPTION SERIAL CONSOLE GP1, GP0

Runs at 115,200 baud. 

Stackup

Using 4-40 standoffs for stackup.

With DB-9 Breakout and FTDI-49MM plus DCE cards.