First brought online in 2005, Model 00 or Mother Chip as she was named by young Richard Cho is the original of the PAUs. While Elizabeth and Richard have upgraded her as best they can, her programming and build are fairly clunky and it would take a very risky overhaul to really bring her up to date. So, she's merely a respected relic that has to be carefully cared for and frequently charged.

She has never been with anyone but the Cho family, so she speaks with a British accent when she does process what is being said to her. Her arms are shaped rather like a Barbie's when idle, and her charge lasts for only a few hours while newer models can run a few days on one charge. 

Sometimes, though--it looks like she's blinked.