Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: What and where  is an ExpansionPort 3 on the HP pavilion dv6?
Document: I highly recommend this model for anyone with the HP #3 docking port connector.
Nice!The unit doesn't come with a power supply, but it is also about 1/2 to 1/3 the price of a full docking station. I had to buy another power supply for home use. Also, I don't know if this is fully compatible with non HP laptops, but if you have an HP laptop, this is great.
I have an old HP L2005cu laptop. Still a great machine after upgrading to a bigger, faster hard drive. The dock works just great but only after I separately purchased an expansion 2 to expansion port 3 converter. Even HP documentation was unclear which type the quick dock was but the Amazon info lead me to believe it was a port 2 type. The converter was an extra $20  but the combo is just what I needed.
The HP Quickdoc is a very nice docking station and helps a lot when using with a laptop. Although, beware, the power plug of a HP Pavilion dv7-1135nr will not work with this docking station. Something they left out of the product description. I had to purchase a new power cord to match the product power receptical. Good product, good price, fast delivery.
i bought an hp pavilion tx1000cto laptop with a 160gb hard drive and i use it for school, work, and entertainment. one problem i was having was having to disconnect all my cables from my laptop everytime i wanted to take it somewhere else (ie to my home entertainment system to watch tv shows i d/l) and this product allowed me to do it with ease.
I'm generally very pleased and this dock has eliminated our need for desktop PC. Yes, the dock is missing a power supply, but an easy work around is to run a 3 prong extension cord up to the docking station so that you can easily unplug the laptop's original power supply when you need to take it with you. The dock has worked great for us except that the computer will not go to sleep automatically.
This product does everything I could ask it to do. The 6 powered USB ports are nice. The power supply through expansion port 3 is one of the coolest features. Only complaint is cable must be connected/disconnected when logged into windows, NOT WHILE AT LOGIN SCREEN otherwise display needs to be reconfigured each time.I do not use the digital audio or composite video so cannot review those aspects.
Likes:1) 6 powered USB ports (great for mouse, keyboard, external drives)2) Component, SVGA, composite and VGA video out (can connect to almost any monitor)3) Coax digital audio out and analog stereo mini-jack out4) Microphone in5) EthernetI can unplug the dock cable and I am off. The only time I use the USB ports on the laptop are for a flash memory stick.
In spite of stating that the Dock was compatible with the dv7 series of HP laptops it indeed was not.
I previously had a desktop with half a dozen things plugged into it before I bought my HP dv2500 laptop.
Answer: left had side at back