yes there are...

Typically (courtesy DIYCNC)
1 Charge pump signal Enable
2 X Direction X Axis
3 X Step X Axis
4 Y Direction Y Axis
5 Y Step Y Axis
6 Z Direction Z Axis
7 Z Step Z Axis
8 A Direction A Axis
9 A Step A Axis
10 Input 1 Input pin
11 Input 2 Input pin
12 Input 3 Input pin
13 Input 4 Input pin
14 Output signal Output pin
15 Input 5 Input pin
16 Spindle pulse Output pin
17 Relay 1 Output pin
18-25 Ground GND