Pros: Drops right into Linux, no extra drivers needed. works well, shows up as /dev/ttyS[0-3]
More than $100.00 cheaper than similar products.

Cons: None that I can think of

Pros: Cheap, 4 port serial card, only uses one PCIe slot.

Cons: Not reliable. Two months ago we installed 13 new PCs on production lines, and needed to expand their serial inputs. We bought 14 of these cards (13 for the PCs plus one spare), and at first they seemed to work great. We have a barcode printer and a scale plugged into the serial card, and during our trial phase where we only had two of the new PCs running, they seemed to work fine. Once we brought all of them online though, we found that only about half the cards would work all the time. The other half will intermittently stop communicating, and no number of restarts, driver reinstalls, BIOS resets, or even Windows reinstalls will fix them.

Manufacturer Response:

Dear Customer,

What you are experiencing can be cause of a driver issue. If you are deploying this card in a supported operating system, it / they should be functioning without any issues. We suggest you go to our website to download the latest drivers for this card to possibly fix your problem. If this does not solve your issue, do not hesitate to contact our support team for further assistance.

Thank you for purchasing one of our products, and for leaving us your feedback. We value all positive and negative feedback.

Feel free to contact us anytime @ support@sybausa.com

Regards, SYBA CST 09192012

Pros: four ports with real UARTs. Top speed of 230K. Preliminary testing with Zmodem had no problem moving multi-megabyte files at 230K.

Cons: Took multiple tries to get the driver to install. Instead of using the standard Windows driver installation, you have to run an executable that takes many minutes and may not work. Windows Vista 64.

Other Thoughts: This looks like a nice tool for legacy serial applications, or for industrial communications.

Pros: It's a cheap card, very fast interface to software. Once I found the right Linux kernel that worked with the driver, it worked well.

Cons: Tried using this with Fedora Core 14. No luck. The 2.6.34 kernel wouldn't even compile the latest source from the website. Finally dropping back to Fedora Core 12 allowed this. Strange behavior, I have to manually modprobe after boot up as superuser and set permissions on the 4 new tty ports (/dev/ttyF0 to ttyF3) to allow them to be accessed by other. Working on a modification to start up script to allow this.

Other Thoughts: The driver on the disc and the website havent' been updated after the initial version. The serial port structures and interfaces changed around 2.6.33 to the point where it would take a serious driver rewrite to work. 2.6.32 was the last one compatible with their driver. I had to use Fedora Core 12 to get this kernel. Also, as stated above, the changes to /etc/rc5.d/ doesn't seem to auto-detect on start-up. I'll have to modify the local.d startup script to do a depmod -A and a modprobe 99xx call via sudo manually, then set the permissions of each tty port using chmod 777 /dev/ttyF0-ttyF3 before I can reliably have these working the way I need them. Besides that, things have gone well so far. Probably works great with windows.

Pros: Worked fine for me on Linux (SuSE 11.3 with 2.6.34 kernel). No special drivers were needed; it shows up as /dev/ttyS0 to /dev/ttyS3. Just ignore the driver disk that comes with it.

Cons: It fits in a half-height slot, but does not include a half-height bracket. I lucked out and found a suitable bracket in my junk box.

Other Thoughts: Most cost-effective way to add 4 reliable serial ports to a modern Linux PC with PCI Express slots. I did not try installing in on a Windows PC, though, so I have no idea how well it would work there.

Pros: Probably works great in Windows.

Cons: WILL NOT WORK with any current distribution of Linux, for example Ubuntu 9.04 (kernel 2.6.28). The source-code driver will not even compile (missing structure elements, API changes, etc). Driver is written by MOSCHIP (chipset mfr), but Syba advertises that it works with "Linux kernel 2.6.11 or higher". Not true. Direct from Syba's technical support in an email:

"Currently, this driver does not support Kernel 2.6.28 on Ubuntu. Unfortunately, the chipset manufacturer has not released any driver for this new kernel. The linux driver for MSC9901 currently only tested on Kernel version 2.6.11-1.1369 that is available with Fedora Core 4, Kernel version 2.6.15 on Fedora Core 4, Kernel version 2.6.18 on Fedora Core 4 and Kernel version 2.6.21 with FC7."

Until Syba/MOSCHIP updates their drivers, do not purchase this board if you expect Linux support.

Other Thoughts: $30 is a great value for a 4-port PCI-Express serial port adapter, and it probably works just fine in Windows. Just wish it actually worked as advertised in Linux.

Also, the MCS9901 is used in other multiport serial boards by other manufacturers. Those boards will have the same issues. For Linux support, choose a board with a different manufacturer's chipset.