Connected devices, up to
The largest number of devices that can be simultaneously connected to the modem via Wi-Fi (see "Connection").
The presence of this limitation is due to the fact that processing network requests from several devices at once requires a fairly large amount of computing resources, and there are not so many of them in miniature electronics like wireless modems. However, even inexpensive models can support about 5 – 6 devices, which is more than enough for most cases; and in more advanced modems, this number can reach 10.
Effective range
The greatest distance at which the modem's built-in router is capable of providing communication via the Wi-Fi interface (see "Connection").
It should be taken into account that in fact the range strongly depends on a number of factors that are not related to the main specs of the modem: the presence of interference and obstacles in the signal path, the specs of the Wi-Fi module of the connected device, the battery charge in this device or the modem itself, etc. Therefore, the actual range indicators can be noticeably lower than the claimed ones: for example, when working through a wall, they are noticeably reduced. However, this spec quite clearly describes the overall range of the device, and comparisons of different models on it are quite acceptable.
Also note that it does not always make sense to purchase a device with a maximum range — although a long range provides additional convenience, it requires high transmitter power, which significantly increases the size and price of the modem. Therefore, when choosing, it is worth proceeding primarily from the intended scenarios of use. For example, if you need a 3G connection to access the Internet on the road from your tablet, a range of several metres will be enough. But for installation in a large private house, it makes sense to look for a model with increased effective range.
Memory card slot
The presence
of a slot for memory card in the design of the modem. Memory cards are very popular in modern electronics as removable storage media; in wireless modems, there are two main options for working with them. The first one provides use as an external card reader, for exchanging information between the card and the device to which the modem is connected via USB (see below); Simply put, installing a card turns the modem into a "flash drive" with removable storage. And in models with Wi-Fi (see "Type"), it may also be possible to work as a server that provides access to the contents of the memory card to all wireless devices connected to the modem. As for the types of cards, the most common support for the microSD standard is that they are small enough to be easily combined with compact wireless modem cases. Note that even within the same standard of memory cards there are several varieties, and before buying it's worth to clarify which of them the device is compatible with.
Operating time (internet browsing)
The maximum operating time of the modem with battery power (see "Power") on a single charge in Internet browsing mode. Such power is typical for Wi-Fi routers, therefore, usually, Internet browsing is supposed to provide access to the World Wide Web for an external Wi-Fi device.
This spec is the main indicator of battery life for any battery-powered modem, because it describes the time of using it for its main purpose without recharging. At the same time, you should know that this indicator is measured under certain "perfect" conditions; the actual operating time depends on a number of factors, including the intensity of browsing, the amount of data transferred, the number of connected devices and the distance to them, the cellular network signal strength, etc. Therefore, in fact, the battery life of the modem may be somewhat lower. Nevertheless, it is quite possible to compare different models with each other according to the operating time stated in the specs.
Operating time (standby)
The maximum time the modem can operate on battery power (see "Power") in standby mode on a single battery charge.
This mode can be described as the standby mode. It assumes that the device is turned on, its operating circuits are powered and ready to respond to an incoming signal or user command at any time, but no data exchange occurs and no features work. This indicator is not as important as the Internet browsing time (see above), but it is also of practical importance and allows you to evaluate the battery life of the device — after all, during breaks between communication sessions, the modem is in standby mode.
