Wi-Fi
Wi-Fi connection speeds, more precisely, Wi-Fi standards supported by a modem with the appropriate capabilities (see "Type", "Connection").
— Wi-Fi 3 (802.11g). A further development of the Wi-Fi 1 (802.11b) standard, developed primarily for increasing connection bandwidth (2.4 GHz) and introduced in 2003. 802.11g hardware is fully backwards compatible with 802.11b, so even the simplest of today's Wi-Fi devices support both of these standards.
— Wi-Fi 4 (802.11n). The Wi-Fi standard, which is a further development of the formats described above — in particular, by supplementing them with support of MIMO technology (distribution of input and output between several antennas). Introduced in 2009. The main operating frequency is 2.4 GHz, but there are devices supplemented with a 5 GHz band.
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Wi-Fi 5 (802.11ac). Built on top of 802.11n, introduced late 2013. The main improvements were the increase in the number of streams at the second frequency (5 GHz) and the introduction of more advanced MIMO and modulation standards, which increased the throughput accordingly.
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.
