ThinkPad Port Replicator

IBM ThinkPad Port Replicator The Port Replicator contains basic pass-through connections for notebook ports, including power pass-through. It comes without integrated power supply but provides the same AC port as found in a ThinkPad, so you need to use either your Thinkpad AC adapter or another IBM AC adapter. Besides all the pass-through ports the Port Replicator comes with an On/Off switch and a slot for a cable lock (only for the dock though). Features Ethernet (RJ-45) Modem (RJ-11) USB (1-port) DVI (only works with TP A2*p models) VGA Serial (9 pin) Parallel (25 pin) PS2-keyboard PS2-mouse Diskette drive Audio line-in and line-out Kensington Lock connector Power button Pros & Cons Positives: Inexpensive Negatives: Requires AC adapter, only one USB port, doesn't secure Thinkpad Compatibility: X20/30 series, T20/30 series, R30/31 series, and A20/30 series Warranty: One Year

DVI pass-through

DVI pass-through on the Port Replicator is only supported with ThinkPad A20p, A21p and A22p models.
LCD monitors are getting larger and higher-resolution. Currently, DVI based on 165MHz TDMS transmitters can only (officially) support 1600x1200x32 at 60Hz, which is the resolution of your average 20" non-widescreen LCD. IBM's driver support for this resolution through DVI ports on docks has been inconsistent. Also in Linux you might experience problems even with this resolution and IBM officially states that the pass-through DVI port only supports resolutios up to 1280x1024.