Does it matter whether I buy ExpressCard, PCMCIA, or USB?

plunk10 · EVDO Newbie Joined: 19 Aug 2008 Posts: 10

Greetings forum. My lady has recently purchased a new Lenovo R61i laptop. From doing some research, it looks to be capable of accomodating the ExpressCard54 cards, and PCMCIA cards. Obviously it has USB ports as well.

Since this laptop has few USB ports, I'd like to save those for other potential uses.

Is there much of a difference between using an ExpressCard, PCMCIA Card, or USB for EVDO modems?

Currently, I'm strongly considering the Kyocera KPC680 ExpressCard54 for the laptop. Should I reconsider and go PCMCIA, or USB?

plunk10 · EVDO Newbie Joined: 19 Aug 2008 Posts: 10

I'm hearing comments on other forums that USB is not the way to go. Here's an interesting tidbit from wikipedia about express cards.

[quote=wikipedia]The major benefit of ExpressCard technology over the previous PCMCIA CardBus PC card is a dramatic increase in bandwidth, afforded by the fact that the ExpressCard has a direct connection to the system bus over a PCI Express x1 lane and USB 2.0, whereas CardBus utilizes an interface controller that only interfaces with PCI. The ExpressCard has a maximum throughput of 2.5 Gbit/s through PCI Express and 480 Mbit/s through USB 2.0 dedicated for each slot, versus CardBus's shared 1.06 Gbit/s bandwidth.

[/quote]

It would be interesting to know if the Kyocera card interfaces with pci express, or through USB. If PCI express, it sounds like it would have a higher bandwidth capacity. If it utilizes the USB bus, then it sounds like the old pcmcia card has the better capacity.

Mackieman · EVDO Junkie Joined: 31 Oct 2005 Posts: 490

I think you're confusing physical interface speed with actual performance. The KPC680 connects to your laptop via a USB interface that runs over an ExpressCard physical interface. With that said, the, "slowest" physical interface (USB) is still around 228 times faster than the fastest EVDO connection you'll ever experience. Though USB has a theoretical maximum throughput of 480mbps, the real-world throughput depends greatly upon the hardware involved but generally ranges about 15 to 20mbps. EVDO Rev. A has a theoretical maximum throughput of 3.1mbps, with a real-world throughput level of 800kbps to 1.2mbps utilizing a high quality connection.

In sum, the physical interface used by the device will in no way limit the performance of your EVDO connection. More people are buying USB devices these days because of how ubiquitous USB is on both PCs and Macs. Some Macs don't have ExpressCard and none of them have PCMCIA anymore, and the same story is true with newer laptops though to a lesser degree. USB will enable you to use the widest range of host devices, but the ExpressCard or PCMCIA card will work just as well.

Alex · Posted: Wed Aug 20, 2008 10:38 am Post subject:

We wrote an article about this. Wanna read it? here it go:

Which is Faster? EVDO ExpressCard, USB, or PC Card?
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plunk10 · EVDO Newbie Joined: 19 Aug 2008 Posts: 10

Mackieman, thanks for replying Smile

With USB, I'm just worried about use of other USB devices (i.e. mouse) affecting the bandwidth or overall performance of another USB device acting as a modem.

My reasoning for this goes back to the early days of cable modems where people that didn't have ethernet cards were forced to use USB for their network connection. Back then, performance suffered considerably when people went that route.

edit: Alex, I just saw your reply, and I want to thank you as well Smile

. The article explains everything perfectly.

nschwen · Posted: Wed Aug 20, 2008 11:52 am Post subject:

The previous replies cover the reasoning well. I've been through three EVDO modems now (upgrading, changing carriers, etc), and after that experience my form-factor of choice for my last purchase was USB. I wish my older cards were USB as well, as being PCMCIA cards, they're now semi useless to me. My new laptop has an ExpressCard slot vs. PCMCIA, so I can't use those cards anymore outside of the older router I have that supports that. My new MBR1000 router accepts only USB or ExpressCard. If the old cards had been USB form factors, I could use them in any machine I own, even the desktop. (Yes, PCMCIA/Express add-in cards can be had, though they sometimes have their own quirks)

Bottom line for me was that USB can be used anywhere, in any machine I own now, or am likely to in the future. New laptops/routers likely won't have PCMCIA slots. Some will have ExpressCard slots. All, from desktops to beefy laptops, to 'ultra portable' laptops, to EVDO routers; will have a USB port. USB is very very well established, and unlikely to go away any time soon.

Everything I've read, and my own personal experience, points to there being absolutely no performance difference between the EVDO form factors. In fact, since a USB modem could in theory be moved more (see USB extender cables that hold their form, like the one that comes with the Compass597), it could actually perform better since you can move it a bit to get a better signal.

USB offers ultimate flexibility with zero performance cost. The choice is pretty clear from my standpoint.

Mackieman · EVDO Junkie Joined: 31 Oct 2005 Posts: 490

I remember the days of early cable rollouts. Those connections were USB1.1 which is significantly slower than USB2.0. 12mbps versus 480mbps, and USB1.1 often saw real world speeds of less than 1mbps. That's why you saw performance drops on cable connections that were 1.5 and 2mbps. That situation is not applicable in the world of EVDO. Smile

Jim_in_VA · Posted: Wed Aug 20, 2008 1:17 pm Post subject:

nschwen makes a good point ... kinda hard to stick that ExpressCard in a window for better signal
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plunk10 · EVDO Newbie Joined: 19 Aug 2008 Posts: 10

Jim_in_VA · Posted: Wed Aug 20, 2008 2:30 pm Post subject:

The cables that hold their form are less than a foot in length ... ala the included Sierra Compass cable. Money well spent would be a 10-15 ft extension that lets you place the modem in a optimal position for a better signal. But yeah, a swivel will work if you wanna keep it tight.
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Alex · Posted: Wed Aug 20, 2008 2:45 pm Post subject:

Jim_in_VA · Posted: Wed Aug 20, 2008 2:49 pm Post subject:

ya tie a couple of pipe cleaners on a short one Alex ... voila! Rolling Eyes

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Alex · Posted: Wed Aug 20, 2008 2:55 pm Post subject:

afroninja92 · EVDO Newbie Joined: 08 Jan 2008 Posts: 9

I saw an article you guys had a while back that showed that the 720s(pcmcia) had somewhat lower ping times than the u720(usb), is that still relevent on the newer modems?