Comparison Sierra AirCard 771S vs ZTE MF90

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.

The generation(s) of mobile networks supported by the modem.

Note that this spec is rather conditional and generalized, since one generation usually includes several data transmission technologies (see below), and the set of these technologies may vary in different mobile networks and in different modems. Therefore, it is possible to evaluate the compatibility of a device with a specific cellular network using this parameter only approximately. Nevertheless, generation data may well come in handy at the preliminary selection stage: they allow you to at least select the generation you are interested in and then search further among models that are compatible with it.

As for specific generations, today they are as follows:

— 2g. Communication standards of the second generation implemented through mobile networks of the GSM standard. Support GPRS and EDGE transmission technologies. Due to low bandwidth, today they are considered obsolete and are gradually being replaced by the next generations of communication. However, this process is uneven, and in some countries 2G is still the main mobile standard (although everything is moving towards changing this situation). Also note that even the introduction of newer standards does not mean the replacement of GSM — many operators keep this technology as a spare and intended for the simplest mobile phone models. Actually, the second generation in its pure form is pract...ically never found in cellular modems — it complements more advanced standards.

— 3G. Communication technologies of the third generation. Includes W-CDMA, HSUPA, HSDPA, and HSPA+ technologies, and in CDMA networks, EV-DO Rev.A and Rev.B. Significantly outperforms second-generation standards in terms of both pure throughput and additional features. And the data transfer speed itself can be comparable to that of a fixed wired Internet connection, which allows you not only to comfortably browse the web, but also use video calls, listen to streaming audio, etc. However, in fact, the quality of communication depends both on the specific technologies used, on the signal level, and the workload of base stations, etc.

— 4G. The fourth generation of communication, the most advanced to date. It includes WiMAX and LTE technologies, which significantly exceed not only 3G standards in terms of data transfer speed, but also the usual fixed wired Internet connection via Ethernet. However such a connection is not cheap.

Data transfer technologies supported by the modem.

— GPRS. The oldest communication technology in use today. It was developed as a standard for GSM cellular networks, allowing data to be transmitted in parallel with voice communications and text messages, as well as charging network access by the amount of data transmitted, and not by connection time (as in the previous CSD standard). At the time of its creation, it was very progressive, but now it is considered completely obsolete and is used only in cases where more advanced standards cannot be used.

— EDGE. A technology created as a modification of the GPRS described above, which would increase the channel throughput and improve communication reliability. Otherwise, this standard is completely similar to GPRS in terms of its main practical features.

— W-CDMA. One of the early third generation ( 3G) communication standards. Used in UMTS networks. One of the main advantages of such networks is the ability to build networks based on the existing GSM infrastructure. Therefore, UMTS, and specifically W-CDMA, is being used by many mobile operators in the early stages of their transition from 2G to 3G.

— HSUPA. Third generation (3G) communication technology, an evolution of W-CDMA described above. The name stands for "Hi...gh-Speed Uplink Packet Access" — high-speed packet data transmission in the "from the subscriber" direction. This, in fact, describes the purpose of this technology: it increases the speed of data transfer from the modem to the base station, which can be useful for some specific tasks — for example, video communications.

— HSDPA. Further, after HSUPA, improvement of the W-CDMA standard (see above). It belongs to third generation (3G) networks, but is considered an “extended” standard, which is why HSUPA-enabled networks can be referred to as 3.5G, 3G+, etc. The name itself — "High-Speed Downlink Packet Access" — translates as "high-speed packet data transmission from the base station to the device."

— HSPA+. Today's most advanced third-generation communication standard based on UMTS networks (W-CDMA). Thanks to a number of improvements, it allows to achieve higher speeds than the options described above, approaching fourth-generation networks in terms of capabilities; therefore, sometimes conventionally referred to as 3.75G.

— WiMAX. Initially, WiMAX was created in two versions — "mobile" and "stationary"; the vast majority of modern cellular modems use the second option. It belongs to the fourth generation standards — 4G (whereas "mobile" was a competitor to 3G technologies, although sometimes it is also referred to as a 4th generation connection for marketing purposes). Some time ago, WiMAX was actively promoted as an alternative to wired broadband Internet connection (in particular, as the best option for areas, where it is difficult to reach the cable). However, now this standard is gradually losing popularity — in particular, in connection with the development and promotion of a more advanced LTE (which also does not have a division into "mobile" and "stationary" varieties).

— LTE (up to 173 Mbps). The fourth generation cellular communication standard, the most popular 4G technology today — in particular, due to the fact that it is a further development of W-CDMA/UMTS and can be implemented by improving existing networks (both UMTS and CDMA2000). Another reason for the popularity is the same convenience for both stationary and mobile equipment. On the other hand, when choosing a modem of this standard, you should keep in mind that LTE bands and channels may differ in different countries, so the support of this technology does not guarantee compatibility with a particular network. It should also be taken into account that in some countries LTE networks are only at the deployment stage, and in some they are not available at all.

— EV-DO (Rev.A). EV-DO is a third-generation (3G) data transmission technology used in CDMA mobile networks (not to be confused with W-CDMA, built on another basic standard — UMTS). Note that in some countries this type of 3G network became widespread much earlier than W-CDMA and its modifications, and for a number of technical reasons it is mainly used for data transmission — that is, for the operation of 3G modems. As for Rev.A, this is the second and most common version of the EV-DO standard.

— EV-DO (Rev. B). The third version of EV-DO technology, the development and improvement of Rev.A; see above for details. Here we note that this standard is also often used as a 3G data connection; its coverage area is not as extensive as the previous version, but still covers most major cities and their surroundings. It is also worth considering that in order to use all the features of Rev.B, you need a modem that supports this version, and not all modern EV-DO devices can do this.

When evaluating the capabilities of a modem, note that the speed values given for each technology are the maximum, which in fact is achievable only under perfect conditions. The actual values of the speed, usually, are lower than the potential ones; they may depend both on the specs of the network, signal strength and other technical issues, and on the policy of the operator and the conditions of a particular tariff.

— USB plug. The presence in the design of the modem of its own USB plug, which allows you to connect the device to a computer directly. Such a connection provides a device with a USB port with Internet access, and the power necessary for the operation of the modem is also supplied via USB.

— microUSB. A smaller version of the USB connector (see above), used primarily in Wi-Fi modems (see "Type") that can work autonomously and do not require a constant connection to another device. At the same time, in 3G/4G modems, microUSB usually looks like a socket, not a plug, and a special cable is used to connect. This interface usually plays the role of a general-purpose service connector: the battery is charged through it, and it is also connected to a PC or other device to manage settings, update firmware, etc.

— USB. Wired interface, the most common and universal modern standard used to connect peripheral equipment to various electronic devices, ranging from computers to smartphones and even wireless modems. In this case, the full-size version of the USB connector is meant. It is usually installed in classic modems (see "Type") and has the form of a plug, with which the modem is connected to a control device (PC, laptop, tablet, etc.). Power is usually supplied through the same connector.

— ...>USB-C. Connector, in its functional features similar to the paragraph above. With the exception of the symmetrical form factor and the use of more modern technologies.

— LAN (RJ45). Classic wired connection via a cable with an RJ-45 connector. Also known as "LAN". Nowadays, it is one of the most common methods of wired Internet connection, and is also widely used in local networks. With it, you can connect a laptop or PC directly to the modem via a cable and not bother with a Wi-Fi connection. In addition, such a connection can be faster (depending on the speed of the LAN).

— ExpressCard. A connection interface mainly used in laptops. Peripheral devices of this standard, including wireless modems, have the form of cards, when connected, they are installed in a special slot in the device. It should be taken into account that there are two ExpressCard form factors — 54 mm and 34 mm, and 34 mm cards can be used without restrictions with 54 mm slots, but not vice versa. Therefore, when choosing such a modem, it is worth clarifying the correspondence of its form factor to the planned slot. However, this standard is gradually disappearing from the scene, being replaced by more advanced interfaces — in particular, USB 3.0.

The presence of a connector for an external removable antenna in the modem design. The meaning of all external antennas is described above; here we note that the connector makes it possible to use rather large antennas with the modem, which significantly exceed the capabilities of stock antennas (both internal and external non-removable ones). In addition, the user can choose the antenna at his discretion.

The presence of a display in the design of the modem. Even the simplest screens used in modern modems are very versatile and capable of displaying almost any service information about the operation of the device (and sometimes not only purely service information). Due to this, this feature provides much more opportunities to inform the user than various indicators. At the same time, we note that this feature is found only in Wi-Fi modems (see above) designed for stand-alone use. This is due to the fact that in models that are connected to another device via USB, the screen of the external device is used for displaying this information, and it simply does not make sense to equip the modem with its own display.

The capacity of the battery installed in the modem with the corresponding type of power supply (see below).

The higher the capacity, the longer the battery is able to work without recharging, all other things being equal. However, note that the situation of "other things being equal" is almost not found in modern wireless modems. First, different data transmission technologies (see above) have different power consumption; secondly, even models supporting the same standards can differ in power consumption (and battery life) due to design differences. Therefore, this indicator in most cases is purely reference information, and even very similar models can only be compared approximately. When choosing, it is worth focusing primarily on the claimed specs of the battery life (see below).

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.