ExpressCard is PCMCIA's (subsumed by the USB-IF) portable, removable, expansion technology to replace PC Card and PC CardBus (sometimes mistakenly called PCMCIA Cards). ExpressCard holds several advantages over PC Card some of which are enumerated below.
Our ExpressCard 34 to PCMCIA PC CardBus 16/32-bit Read-Writer Express2PCC allows computers with ExpressCard slots to use either 16-bit legacy PC Cards or 32-bit PC cardbus Cards. Express2PCC works with host systems featuring native ExpressCard 34 or ExpressCard 54 slots, or an installed PCIe to ExpressCard adapter. If the host operating system supports the PCMCIA PC Card, it should also work in conjunction with the Express2PCC. Sonnet's Qio device provides support for Panasonic P2 PC Card Memory devices on both Mac OS X and Windows. The Qio is available with either ExpressCard, PCIe, or Thunderbolt connections to the host system.
For PCIe based ExpressCards — in a word, no. However, it is useful to explain why this is the case. 32-bit PC Card CardBus card don't provide enough bandwidth to emulate ExpressCard. Furthermore, ExpressCard cards are completely different from PC Cards in voltages, form factor, physical connectivity and bus technology.
While the PCMCIA ExpressCard specification requires all host adapters and slots to support both PCIe and USB 2.0 portions of the ExpressCard bus, several products are now on the market that only support the USB 2.0 mode. While this technically breaks the specification, many consumers have been clamoring for such a device. In response to such demand, products are now appearing on the market that bridge between PCMCIA PC Card and USB 2.0 based ExpressCards. Several new devices behave like USB 2.0 hubs, routing an ExpressCard's USB 2.0 through a PCMCIA PC Card slot. PCMCIA PC Card to USB 2.0-Mode ExpressCard adapters are available as 32-bit and 16-bit PCMCIA PC Card varieties. PC Card USB 2.0 mode ExpressCard host adapters cannot work with any PCIe based ExpressCards. This is true for USB to USB 2.0-Mode ExpressCard adapters like our MicroU2E series as well.
ExpressCards come in two form factors: ExpressCard 34 and ExpressCard 54. The form factors share the same dimensions except for width, from which the names of the form factors are derived. ExpressCard share a length of 75mm and a depth (or thickness) of 5.0mm — the same depth as Type II PC Cards. Both the widths and shapes of the two ExpressCard form factors are different, but the portion of the card which connects to the card slot are an identical 34mm. ExpressCard 34 cards are 34mm wide and rectangular in shape. ExpressCard 54 Cards are 54mm wide at their widest point and 34mm wide at the connection point, creating a shape often referred to as a "Fat-L". Either form factor is allowed additional volume extending outside of what would be considered the flush portion of an inserted card. This is referred to as the extended portion of the card and ExpressCards with such a configuration are referred to as extended cards. The extended portion can exceed the card dimension in any axis, but there are obvious practical limitations to how much. For an excellent example of an ExpressCard with an extended portion on two axis (depth and width) see: ExpressCard 34 to CompactFlash Memory Card Adapter. For an explanation of how ExpressCard modules are used in the two types of ExpressCard slots, please see ExpressCard Slotting.
ExpressCard slots come in two varieties; those designed for both ExpressCard 54 and 34 cards, and those for ExpressCard 34 cards only. ExpressCard slots are required to provide both PCIe and USB 2.0 functionality, regardless of their size. ExpressCard 54 slots, as pictured in figures A and B on the right, are able to accept both 54 and 34 cards. What PCMCIA describes as a "novel guidance device," which seen in the lower left corner of figures A and B, physically guides an ExpressCard 34 device to the connector part of the slot. Since the connection part of the card for both types of ExpressCards is identically 34mm, this scheme provides an elegant solution for utilizing both types of cards. Conversely, only ExpressCard 34 cards fit in ExpressCard 34 slots as pictured in figure C. Paying attention to this last fact is important when shopping for ExpressCard products, if a device only has an ExpressCard 34 slot, then only shop for ExpressCard 34 devices.
PCMCIA literature has expressed that systems deploying multiple ExpressCard slots should lay them out adjacently on a horizontal plane rather than the "stacked slot" convention employed by PC Card slots.
While it may have seemed a sound idea to engineers designing the original ExpressCard standard, one of the more perplexing — and troublesome — aspects of the design has been using ExpressCard/34 cards in ExpressCard/54 slots. In practice, ExpressCard/34 cards, even when properly seated, aren't stable when inserted in the larger ExpressCard slots. The gap between the card and the larger slots allowed cards to be easily dislodged or come loose. This problem is more evident when ExpressCards with large "extended card" portions, and/or with cables attached to them. When cards come loose and disconnect during operation, they drop signal, or worse, can damage the ExpressCard and even the ExpressCard slot. This is especially true for cards providing electrical current, like many Serial I/O ExpressCards.
The SlotGuardExpress ExpressCard/34 Stabilizer Insert for ExpressCard/54 Slots protects against ExpressCards being dislodged from their slots. SlotGuardExpress is an inexpensive, non-conductive insert that attaches to the side of an ExpressCard/34 to eliminate the free-play between the card and the ExpressCard slot. SlotGuardExpress is available as a product for individual end users and for Original Equipment Manufacturers (OEM who want to include it with their ExpressCard/34 products. SlotGuardExpress puts an end to disrupted connections and equipment damage caused by ExpressCards moving side to side (laterally) in larger slots.
| Performance differences between ExpressCard versions | ||||
|---|---|---|---|---|
| ExpressCard 1.x (USB 2.0) |
ExpressCard 1.x (PCIe 1X) |
ExpressCard 2.0 (USB 3.0) |
ExpressCard 2.0 (PCIe 2.0 1X) |
|
| Throughput (max) | 60 MB/sec. (480Mbps) | 250 MB/sec. per direction (2.5Gbps per direction) | 640 MB/sec. (5.0Gbps) | 640 MB/sec. per direction (5.0Gbps per direction) |
ExpressCard 2.0 upgrades the underlying bus standards to PCI Express (PCIe) 2.0 and USB 3.0. Two channel PCIe 2.0 1X technology is capable of 5.0Gb/s per direction, while SuperSpeed USB 3.0's maximum theoretical speed is 5.0Gb/s. Neither bus standard achieves those speeds in practice, but PCIe, lacking USB's latency and encoding issues, comes much closer to its max theoretical speed. The ExpressCard 2.0 update allows for higher performance applications such as native SATA 6Gbps host adapters, but performance-wise still falls short of more modern bus technologies like Thunderbolt.
Available voltages (+1.5V +3.3V) remain the same in ExpressCard 2.0, as do all physical characteristics. Current from various supplies is specified in § 3.3.3 Power Supply Limits of the ExpressCard Standard Release 2.0, which notes that the total max current drawn by a module across all power rails should not exceed 1.75A. Average amperage will be under that threshold.
Currently the only ExpressCard 2.0 capable reader we know of is the Sonnet Echo Thunderbolt to ExpressCard/34 Adapter Pro.
The following table illuminates some of key differences between PCMCIA's PC Card and ExpressCard standards.
| PC Card (16-bit) | PC CardBus (32-bit) | ExpressCard (USB 2.0) | ExpressCard (PCIe 1X) | |
|---|---|---|---|---|
| Throughput (max) | 20 MB/sec. | 132 MB/sec. | 60 MB/sec. | 250 MB/sec. per direction |
| Voltages | 3.3/5.0/12.0 V | 3.3/5.0 V | 1.5/3.3 V | 1.5/3.3 V |
| PC Card | ExpressCard 34 | ExpressCard 54 | ||
| Length | 85.6mm | 75mm | 75mm | |
| Width | 54mm | 34mm | 54mm | |
| Depth | Type I/II/II | 3.3/5.0/10.3mm | 5.0mm | 5.0mm |
There are a number of PCI Express (PCIe) to ExpressCard host adapters and we stock several models with choices including front and rear slot models. Requiring only a single lane PCIe 1X slot and a spare internal USB 2.0 port, PCI Express (PCIe) to ExpressCard drives provide a fully functional ExpressCard 34|54 slot. A smart investment for switching host adapters and other high performance ExpressCards between notebook and desktop computers, PCI Express ExpressCard drives are simple to install and fully conform to PCIe and ExpressCard standards. Although the PCIe specification provides for hot-swap capabilities, there is very limited support under most operating systems for hot-swapping ExpressCards on a desktop computer. The following documents address this in full:
Sonnet's Qio device provides support for Sony/Sandisk SxS ExpressCard Memory devices on both Mac OS X and Windows. The Qio is available with either ExpressCard, PCIe, or Thunderbolt connections to the host system. Another solution is Sonnet's Echo Pro, which is a Thunderbolt to single slot ExpressCard 2.0 host adapter. It is the fastest and least expensive Sony/Sandisk SxS ExpressCard on the market.
The Sonnet's Qio device mentioned above provides support for Sony/Sandisk SxS ExpressCard Memory devices on both Mac OS X and Windows, and is available with a Thunderbolt connections to the host system. Supporting a far wider range of ExpressCards than just SxS, Sonnet's Echo Pro, which is a Thunderbolt to single slot ExpressCard 2.0 host adapter. It is the fastest and least expensive Sony/Sandisk SxS ExpressCard on the market. It also works with ExpressCards providing FireWire, eSATA, and specialized audio and video applications from companies like AJA, Matrox, RME, and PreSonus.
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