Express Cards – What are they & why are there two sizes (34mm & 54mm)
Posted on: June 28, 2011
If you’ve purchased a new laptop PC lately you’ll probably have noticed a new looking slot on the side of it. This is the Express card slot.
ExpressCard technology has been designed to deliver high-performance (they support faster data transfer with lower power consumption) and allow modular expansion to your laptop. If for example you’ve purchased a laptop without a Firewire port but you then find you need Firewire to transfer video from your Camcorder you can add Firewire capabilities with a Firewire Express card.
There are two standard formats of ExpressCard modules:
- 34mm ExpressCards (size:34mm x 75mm)
- 54mm ExpressCards (size: 54mm x 75mm)
Both sizes are 5mm thick, the same as the PCMCIA cards they replace. Both sizes of card use the same connector interface – so the “business end” which actually connects internally inside the laptop is 34mm wide whichever size express card your laptop supports. This is possible because the larger 54mm Express cards are manufactured in an “L” shape with what looks like the corner cut out to enable the interface end to connect internally.
Why two different sizes? Well, it’s to give the system manufacturers greater flexibility than in the past. While 34mm Express Cards are better suited to smaller systems, the slightly wider 54mm Express Cards can support applications that would not physically fit into the a narrower 34mm Express Card. Examples include Compact Flash readers, and 1.8-inch disk drives both of which are wider than 34mm.
Additionally the 54mm Express cards give a little more room for on-board components which in turn reduces the amount of heat generated – sounds incredible but the slight larger card does allow for the heat to be dissipated more efficiently which can be important for some high performance applications
After a slow start there are now lots of Express Cards on the market to allow you to upgrade your Laptop and these include:
- eSATA Express Cards
- Firewire 400 Express Cards
- Firwire 800 Express Cards
- USB 2.0 Express Cards
- Solid Storage Express Cards (up to 32GB of storage)
- Serial Port Express Card
- Parallel Port Express Cards
- CF Card Readers
USBNow carry a wide range of express cards and are always happy to offer any advice and guidance if you have a particular requirement.