How to make AP-1 Serial cable
1. you will need
DB9 Female Connector x1
DB9 Male Connector x1
DB9 Backshell x2
Cable x1, you can use Ethernet cable as the DB cable
Cable connection
Female
2 3 5
Male
2 3 7
AP1
PC2 -- CAS2 RX
PC3 -- CAS3 TX
PC5 -- CAS7 GND
Reference Photo