TMC AI5TT User Manual page 37

Speaker: Pins 1 - 4
This connector provides an interface to a speaker for audio
tone generation. An 8-ohm speaker is recommended.
AI5TT Pentium Baby AT Motherboard User's Manual
Chapter 5 Installation
J20 Pin # Signal Name
1 Speaker out
2
3
4
No connect
Ground
+5V
33