It's been almost a decade since I last used a desktop computer as my
daily driver but I've never been able to acclimate myself to a touch
pad. For me, they are awkward to use and since I have the bad habit of
'lazy' wrists resting on either side of the touch pad, I tend to brush
against it and send my cursor caroming off in random directions. The solution for me has been to use an external mouse and disable the trackpad. To be clear, I am not going in and cutting wires. All major operating systems—Mac OS, Windows, Linux, Chrome OS—offer a procedure to turn the touch pad off and back on. Windows and Mac OS can do this automatically when an external mouse is connected to or disconnected from a USB port. And when I'm using a laptop as part of a permanent workstation, such as my desk at work, I also like to use an external keyboard, just because it gives me greater flexibility to achieve a more ergonomic setup.
To be sure, there are a lot of great third party input devices—keyboards, mice, trackballs, etc. out there but many of them have a problem in common—cables. Over the years I have come to greatly prefer the experience of a wireless input devices. These basically come in two flavors: Bluetooth and USB. The former offers the advantage of not requiring a USB port but this is often at the expense of a stable connection. For that reason, I much prefer a wireless USB mouse or keyboard.
The thing is, not all wireless USB peripherals are created equal. Most such devices come with a dedicated USB receiver that is paired with the device with which it shipped and only that device, which presents two major disadvantages. First, if you have multiple wireless devices, each one requires its own USB port. Second, if you lose the receiver, which today very tiny, the device itself becomes useless. Fortunately, one manufacturer has solved this problem.
Logitech, with its Unifying Receiver system, allows up to six devices—mice, trackballs, keyboards—to be paired with one receiver. By doing this, the disadvantages named in the above paragraph are effectively negated. A keyboard and mouse, or even multiples of each, only require a single USB port to from which to operate and lost USB receivers can easily be replaced.
I have acquired several Logitech keyboards and mice second hand for a pittance from thrift shops and as often as not, the receiver is not present. When I see one that looks promising, I look not only for the receiver but for the asterisk logo, indicating compatibility with a Unifying Receiver. If this logo is present, then I know the device can be used, even if it no longer has its own receiver.
To pair a device with a different receiver, one must download the Logitech Unifying Receiver software from Logitech's Web site, launch it and follow a simple set of on-screen prompts to turn the device off if it is already on and then turn it on to be recognized by the receiver. Once paired, the receiver and input device(s) will work with any computer the receiver is plugged into, regardless of whether the Logitech software is present. But because the software is available only for Windows or Mac OS, users of other operating systems such as Chrome OS or Linux, will need to pair their devices and receivers on a Mac or Windows PC and then transfer the receiver to the Chromebook or Linux computer. On dual-boot systems containing Windows or Mac OS in addition to Linux, one can simply reboot into Linux after pairing under one of the aforementioned supported operating systems.
It should also be noted that while multiple devices (up to six) can be paired with one receiver, the opposite is not true. Multiple receivers cannot be paired with a single device. One cannot, for instance, pair a mouse with separate receivers plugged into two different laptops. One must move the receiver from one device to another. This happens because whenever a device is paired with a new receiver, any previous pairing of that device with another receiver is broken. That said, it is not necessary to re-pair existing devices to a receiver when a new one is added, provided the total is no more than six devices.
The way I see it, Logitech's Unifying Receiver system adds great value to compatible input devices and to my knowledge, no other manufacturer offers anything similar. For this reason, Logitech devices bearing the asterisk logo are the only ones I'll consider buying—new or used, with or without their receiver.
Addendum—Since I have accumulated and used several Logitech wireless keyboards, it would seem appropriate to my impressions of each that I have owned. They are listed in descending order by model number. In general, I will say that none of the keyboards below are actually bad, but the user experience differs greatly.
K850—This is my most recently acquired keyboard and my favorite for several reasons. First, it is the only one I own that is both Windows and Mac OS compatible and automatically detects which platform it is connected to. It can also be paired with up to three wireless receivers. Selecting between them is accomplished via three numbered buttons, just to the right of the F-keys, which double as media keys when pressed in conjunction with either the fn keys on the bottom row. The power switch is located inconspicuously along the right side, just below the top right corner. The crowning glory, though is the ergonomic design of the keys, raised in the middle and lower on the outer edges for a more natural wrist position. It also has a padded, non-slip wrist rest for added comfort.
K520—I actually have two of these, not because I like this model so much, but because the first one I found had significant wear and I subsequently found one in pristine condition. This model is roughly the same size as the K850 and has separate multimedia keys, as well as special functions included on the F-keys. The power switch is located at the top right corner. Like the models below, it is Windows only but will work with Mac OS, although the modifier keys are mapped differently, such that the Windows start key takes the function of the Apple Command key and the Alt key is mapped as the Option key; however, these are easily reversed in the Mac OS System Preferences. The keys are comfortably rounded but their action is a little imprecise—not bad but not great, either.
K360—The most compact of the four Logitech keyboards I own, It has flat, square keys, similar to those of a laptop keyboard. The power switch is located conveniently at the top right corner. It has separate media keys that are small but well labeled. The F-keys double as special function keys. I like the action of the keys, which have a nice amount of resistance. It is my second favorite of the four keyboards.
K330—This is perhaps my least favorite of the four Logitech keyboards I own. It is Iinteresting that it is no larger than the K850, but it feels considerably bulkier. It has a separate row of very small media and special function keys that are labeled in a way that makes them difficult to read. My least favorite feature, however, is the power switch, which is located on the bottom of the keyboard, where it is difficult to reach, especially by feel.
