The Telestrat joystick ports sit either side of the machine and are connected directly to the second VIA which is memory mapped in the range $0320 to $032F.
Telestrat Joystick ports have a +5v line which allows autofire and Atari Mice to be connected.
The mouse connections are the same as the joystick connections, and the port also allows for a second joystick button.
Mice deliver two pulses for X and two for Y.
The detection of where a mouse moves Right or left (Up or down)is Dependant on the leading pulse.
In memory both joysticks appear in $0320 and $032F or Port B and Port A respectively.
Both joysticks appear at the same locations but are selected by the two top bits.
Location $0320 (VIA2 PORTB)
Bit 7 - Enable Left Joystick
Bit 6 - Enable Right Joystick
Bit 4 - Down
Bit 3 - Up
Bit 2 - Primary Joystick Fire Button
Bit 1 - Right
Bit 0 - Left
Location $032F (VIA2 PORTA)
Bit 7 - Second Joystick Button (0 == Pressed)