Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Component | Model 01 | Model 01+ | Model 02 | Model e2 | Model 2+ (Pre-production) | model 03 (China Copy) |
| --- | --- | --- | --- | --- | --- | --- |
| CPU | Transmeta Crusoe 1 GHz | Transmeta Crusoe 1 GHz | Via C7M ULV 1.6 GHz | Via C7M ULV 1.6 GHz | Intel Atom Z540 1.86 GHz | Intel atom Z550 1.2 GHz dual core |
| RAM | 256MB DDR | 512MB DDR | 1GB DDR2 | 1GB DDR2 | 2GB DDR2 | 2GB DDR2 |
| Hard Drive | 20GB HDD | 30GB HDD | 120GB HDD or 64GB SSD | 120GB HDD or 64GB SSD | 120GB HDD or 64GB SSD | 120GB HDD or 64GB SSD |
| Display | 5" Transflective 800x480 LCD | 5" Transflective 800x480 LCD | 5" 800x480 LCD | 5" 800x480 LCD | 5" active matrix 800x480 OLED | 4.8" active matrix 1024X600 OLED |
| USB | 1.1 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Wi-Fi | 802.11b | 802.11b | 802.11a/b/g | 802.11a/b/g | 802.11a/b/g | 802.11a/b/g/n |
| WWAN | n/a | n/a | EVDO from Sprint or Verizon | HSDPA | EV-DO and HSPA | HSDPA 3G |
| Bluetooth | 1.1 | 1.1 | 2.0 | 2.0 | 2.0 | 2.1 |
| Wacom | Yes | Yes (Improved accuracy) | Yes | Yes | Yes | unknown |
| GPU | Silicon motion Lynx 3DM+ | Silicon motion Lynx 3DM+ | VIA VX700 | VIA VX700 | Intel GMA500 | Intel GMA500 |
| Removable Battery | 4,000 mAh or 8,000 mAh | 4,000 mAh or 8,000 mAh | 4,500 mAh or 9,000 mAh | 4,500 mAh or 9,000 mAh | 4,500 mAh or 9,000 mAh | 4,500 mAh or 9,000 mAh |
| Battery Type | lithium polymer | Lithium Polymer | lithium ion polymer | lithium ion polymer | lithium ion polymer | unknown |
| Docking Cable | USB 1.1 | USB 2.0 | replaced by dongle or dock | replaced by dongle or dock | replaced by dongle or dock | replaced by dongle or dock |
| Dock | Zinc stand | Zinc stand | Gloss Black w/ optical drive | Gloss Black w/ optical drive | Gloss Black w/ optical drive | Gloss Black w/ optical drive |
| Ethernet | 10BaseT | 100BaseT | 100BaseT | 100BaseT | 100BaseT | 100BaseT |
| Dongle |  |  | RJ45 & VGA | RJ45 & VGA | unknown | unknown |
| Keyboard | 57 key | 57 key | 58 key | 58 key | 58 key | 58 key |
| Weight | 397g | 397g | 413g* | 413g* | 413g* | 426g* |
Question:
how many models use a usb docking cable?
Answer:
2