9207 com port

[m3rv89]

Hi, i am new to NI products. Recently I am worknig with NI 9207 Analog 16 Channel Input Module.

I encountered some problems.

1. There are four COM ports - PIN9, 10, 28, 29. I would like to know whethere are they all connected to the same ground? 

2. The input circuitry displayed two amplifier diagrams. One is of instrumentation amplifier and the other is  of amplifier. What is the difference?

[Wayne.C]

1 - All pins labled 'COM' are connected together internally on the 9207.

2-9207 has two types of inputs.  AI0-7 are voltage inputs and use a differential configuration.  AI8-15 are current inputs and use a single ended input with a resistor.