What is the null modem adapter included in my order used for? Do I need it?

The null modem adapter included with each Aircable / Airserial device is a typical null modem adapter (the Tx and Rx pins are crossed and the gender is changed) with one exception. Most null modem adapters do not pass-through the connection on pin nine of the D-SUB connector. The included adapter does. This is necessary if power is being supplied to the Aircable / Airserial module through the serial connection instead of the jack on the side of the device.

You will only need the adapter if you plan on connecting your Aircable / Airserial to a serial port or other device with a male connector. If you purchased a telescope adapter cable from AstroCables with your Aircable / Airserial module and will be using it exclusively with that cable, you will not need the null modem adapter.