DSC Unlocker 1.3 (esp32) - Stuck in dsc.loop()
First, I'm a new at this so I may have made some newbee mistakes somewhere.

I'm trying to find the installer code on a DSC PC1500 installed back in 1988 in the hope of integrating my old system into HA.

So the Unlocker 1.3 program appears to get stuck in the dsc.loop().  I presume it is not getting the proper (or any) dsc.status() from the board.  

Here's my setup.  I'm using a Freenove kit with an Espressif ESP32-Wroom-32E chip.  I've followed the wiring instructions as best as I could and soldered everything.  In my sketch I use the esp32 v2.0.17 board  (version 3.x will not compile).  In the preferences in the "Additional board managers URLs" I have specified "https://dl.espressif.com/dl/package_esp32_index.json" and "https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json".  I've successfully compiled and loaded Unlocker 1.3 program in the ESP32 chip using either the ESP2-WROOM-DA Module and the ESP32-Dev Module.  I've connected Pin 18 to DSC Yellow, PIN19 to DSC Green and also PIN21 to DSC Green via a 2N3904 NPN transistor.   I should point out that I also have prepared PIN17 for eventual connection to PGM/AUX(+).  So PIN17 IS CONNECTED to a 10k ohm resistor that goes to a ground pin AND to a 33k ohm resistor that is connected to a 1k ohm resistor that goes nowhere.

My question:  is Unlocker 1.3 able to connect to the DSC Keybus on a PC1500 board (assuming that PGM is configured with PC16OUT disabled, the default)?  If so, what am I doing wrong?