Comparison TP-LINK TL-WR840N vs TP-LINK TL-WR940N

Methods for connecting to the Internet (or other external network, such as in bridge mode) supported by the device.

The classic, most common version of such a connection nowadays is LAN (Ethernet), but this is not limited to this. A wired connection can also be made via ADSL or SFP fiber, and wirelessly via mobile networks (using a SIM card, SIM card 5G or an external modem for 3G or 4G), as well as via Wi-Fi. Here is a more detailed description of each option:

— Ethernet (RJ45). Classic wired connection via a network cable via an RJ-45 connector. Also known as "LAN", although this designation is not entirely correct. Nowadays, it is one of the most common methods of wired Internet connection, and is also widely used in local networks. This is due to the fact that the speed of Ethernet is actually limited only by the capabilities of network controllers; at the same time, even the simplest modules support up to 100 Mbps, and in advanced equipment this value can reach 10 Gbps.

— ADSL. A technology primarily used for wired Internet connections over existing landline telephone lines. This is its main advantage — you can use ready-made lines without fiddling with laying numerous addi...tional wires; at the same time, ADSL works independently of telephone calls and does not interfere with them. At the same time, the speed of such a connection is noticeably lower than via Ethernet — even in advanced equipment it does not exceed 24 Mbps. In addition, ADSL traffic is distributed asymmetrically: full speed is achieved only when working for reception, data transmission speed is much lower, which creates problems for video communication and some other tasks. So nowadays, ADSL is gradually being replaced by more advanced standards, although the complete disappearance of this technology is still far away.

— Wi-Fi. Connect to an external data source via Wi-Fi. By definition, this format of operation is used by Wi-Fi adapters (see "Device type"), as well as by most MESH equipment. (However, if the MESH system package includes both nodes and the main control device for them, then the WAN input can be specified for the control device, and often this is not Wi-Fi). Also, this type of data input can be provided in other types of equipment — in particular, routers and access points (for example, to work in bridge or repeater mode).

— 3G modem (USB). Internet connection via 3G mobile network using a separate external modem connected to the USB port. Most often, we are talking about UMTS networks (the development of GSM mobile communications), the most common in Europe and the post-Soviet space; however, it may also be possible to use modems for CDMA networks (EV-DO technology). These nuances, as well as compatibility with specific modem models, need to be clarified separately. However, anyway, 3G may be a good option for situations where a wired Internet connection is difficult or impossible, such as in the private sector. In addition, some Wi-Fi devices with this feature are equipped with autonomous power supplies and can even be used on the go. The data transfer speed of 3G is close to broadband wired connection (from 2 to 70 Mbps with a normal signal, depending on the specific technology); however, it is less than in 4G networks (see below), but 3G coverage is more extensive, and equipment for this standard is cheaper.

— 4G (LTE) modem (USB). Internet connection via 4G mobile network (LTE) using a separate external modem connected to the USB port. The main features are similar to the 3G connection described above, adjusted for the fact that in this case more advanced fourth-generation networks are used. The data transfer rate in such networks reaches about 150 Mbps; they are not as widespread as 3G-connection, but soon we can expect a change in the situation. In addition, it should be noted that in Europe and the post-Soviet space, LTE networks are usually deployed on the basis of 3G UMTS and GSM networks; so in the absence of full-fledged 4G coverage, modems for such networks can work according to the 3G and even GSM standard.

— SIM card. Connecting to the Internet via a mobile network using a mobile operator's SIM card installed directly in the device. The specific type of supported networks depends both on the capabilities of the router and on the conditions of a particular mobile operator; however, all such equipment is compatible with at least 3G networks, and often 4G as well. The features of these networks are described in detail above (you can also read about the advantages of a mobile Internet connection there). This option is convenient because it allows you to do without a separate USB modem — you just need to purchase a SIM card, the cost of which is negligible. In addition, the use of "sim cards" has a positive effect on compactness and ease of carrying. On the other hand, the built-in mobile communication module significantly affects the overall cost — and you will have to pay for it anyway (whereas a model with support for external modems does not have to be bought immediately with a modem, such devices usually allow wired connection). Therefore, you should pay attention to this option if you initially plan to connect to the Internet through mobile networks.

- SIM card (5G). The ability to operate Wi-Fi equipment in high-speed 5G mobile networks with a peak bandwidth of up to 20 Gbps for reception and up to 10 Gbps for data transmission. Implemented via a SIM card with appropriate 5G support. This standard reduces power consumption compared to previous versions, and it also uses a number of complex solutions aimed at improving the reliability and overall quality of communication - in particular, multi-element antenna arrays (Massive MIMO) and beamforming technologies (Beamforming).

— SFP (optics). Connection via fiber optic cable of the SFP standard. Such a connection can be carried out at high speeds (measured in gigabytes per second), and the fiber, unlike the Ethernet cable, is practically insensitive to external interference. On the other hand, the support of this standard is not cheap, and its capabilities are unnecessary for domestic use. Therefore, SFP is found mainly in professional-level Wi-Fi devices.

The maximum speed provided by the device when communicating wirelessly in the 2.4 GHz band.

This range is used in most modern Wi-Fi standards (see above) - as one of the available or even the only one. The theoretical maximum for it is 600 Mbit. In reality, Wi-Fi at a frequency of 2.4 GHz is used by a large number of client devices, from which congestion of data transmission channels emerges. Also, the number of antennas affects the speed performance of the equipment. It is possible to achieve the speed declared in the specification only in an ideal situation. In practice, it can be noticeably smaller (often by several times), especially with an abundance of wireless technology simultaneously connected to the equipment. The maximum speed at 2.4 GHz is specified in the characteristics of specific models to understand the real capabilities of Wi-Fi equipment. As for the numbers, according to the capabilities in the 2.4 GHz band, modern equipment is conditionally divided into models with speeds up to 500 Mbit inclusive and over 500 Mbit.

The total number of antennas (of all types — see below) provided in the design of the device.

In modern Wi-Fi equipment, this indicator can be different: in addition to the simplest devices with 1 antenna, there are models where this number is 2, 3, 4 and even more. The point of using multiple antennas is twofold. Firstly, if there are several external devices per antenna, they have to share the bandwidth among themselves, and the actual communication speed for each subscriber drops accordingly. Secondly, such a design may also be required when communicating with one external device — to work with MU-MIMO technology (see below), which allows you to fully realize the capabilities of modern Wi-Fi standards.

Anyway, more antennas, usually, means a more advanced and functional device. On the other hand, this parameter significantly affects the cost; so specifically looking for equipment with numerous antennas makes sense mainly when the speed and stability of communication are critical.

Note that antennas intended for mobile communications may also be considered in this clause. So when choosing a model with support for mobile networks, it's ok to clarify this point.

Gain provided by each device antenna; if the design provides for antennas with different characteristics (a typical example is both external and internal antennas), then the information, usually, is indicated by the highest value.

Amplification of the signal in this case is provided by narrowing the radiation pattern — just as in flashlights with adjustable beam width, reducing this width increases the illumination range. The simplest omnidirectional antennas narrow the signal mainly in the vertical plane, "flattening" the coverage area so that it looks like a horizontal disk. In turn, directional antennas (mainly in specialized access points, see "Device type") create a narrow beam that covers a very small area, but provides a very solid gain.

Specifically, the gain describes how powerful the signal is in the main direction of the antenna compared to an perfect antenna that spreads the signal evenly in all directions. Together with the power of the transmitter (see below), this determines the total power of the equipment and, accordingly, the efficiency and range of communication. Actually, to determine the total power, it is enough to add the gain in dBi to the transmitter power in dBm; dBi and dBm in this case can be considered as the same units (decibels).

In general, such data is rarely required by the average user, but it can be useful in some specific situations that specialists have to deal with. Detailed calculation methods for suc...h situations can be found in special sources; here we emphasize that it does not always make sense to pursue a high antenna gain. First, as discussed above, this comes at the cost of narrowing the scope, which can be inconvenient; secondly, too strong a signal is also often undesirable, for more details see "Transmitter power".

The total number of antennas in the router that are responsible for communication in the 2.4 GHz band. For details about the number of antennas, see "Total antennas", about the range — "Frequency range".

The range of the device's Wi-Fi module when used indoors, including through walls.

This indicator is, by definition, less than the range in open space (see below), but it is closer to reality: Wi-Fi equipment is most often used in rooms where the signal has to deal with various obstacles. However note that the figures stated in the characteristics are rather arbitrary: in fact, the communication range will directly depend on the number and type of obstacles, the congestion of the air with signals from third-party electronics, as well as the capabilities of Wi-Fi modules in devices “on the other side of the channel”. However, the difference in claimed range usually corresponds to the difference in the actual range, so it is quite possible to compare different devices by this characteristic.

Also, this information allows you to evaluate the range in open areas (if it is not claimed in the characteristics): usually, this radius is at least twice the claimed range indoors.

The range of the Wi-Fi connection when the device is operating outdoors is in an open area where the signal does not need to overcome obstacles in the form of walls and other foreign objects. In other words, we are talking about the communication range within the line of sight. This parameter can be useful not only when installed outdoors, but also, for example, in a large office space. However, do not forget that the practical range may be somewhat less, because. it also depends on the capabilities of the connected devices and the level of interference.

Also note that according to these data, it is possible to estimate the range of action in the room, if for some reason this information is not indicated in the characteristics. On average, this radius is 2-4 times less than the outdoor range, and for maximum guarantee it is worth taking a factor of 4: for example, for a reliable connection at a distance of 10 m, it is desirable to have a device with a range in open areas of at least 40 m.

The main functions and capabilities implemented in the device.

This category mainly includes the most key functions — namely load balancing (Dual WAN), channel reservation, Link Aggregation, Bluetooth(various versions, including Bluetooth v 5), voice assistant, NAT, MESH modes, bridge, repeater, Beamforming function , firewall (Firewall) and CLI (Telnet). Here is a more detailed description of each of these items:

— Dual WAN. Possibility of simultaneous connection to two external networks. Most often used for simultaneous work with two Internet connections (although other options are possible); at the same time, there are two main modes of operation with such connections — redundancy (Failover / Failback) and balancing (Load Balance). So, in backup mode, the device constantly uses the main channel to connect to the Internet, and in case of failures on this channel, it automatically switches to a fallback option. In balancing mode, both channels are used simultaneously, while the load between them is distributed either automatically (depending on the traff...ic consumption of a particular device) or manually (clearly specified in the settings for specific devices). This allows, for example, to separate the channel for online games from the rest of the connection, minimizing lags and increasing efficiency.

— Link Aggregation. A function that allows you to combine several parallel physical communication channels into one logical one — to increase the speed and reliability of the connection. Simply put, with Link Aggregation, a device can be connected to another device not with one cable, but with two or even more at once. The increase in speed in this case occurs due to the summation of the throughput of all physical channels; however, the total speed may be less than the sum of the speeds — on the other hand, combining several relatively slow connectors is often cheaper than using equipment with a more advanced single interface. And the increase in reliability is carried out, firstly, by distributing the total load over individual physical channels, and secondly, by means of "hot" redundancy: the failure of one port or cable can reduce the speed, but does not lead to a complete disconnection, and when the channel is restored, the channel is switched on automatically.

— Bluetooth. The device supports Bluetooth wireless technology. The meaning of this function will depend on the format of the equipment operation (see "Device type"). For example, adapters with this capability allow you to supplement your PC not only with Wi-Fi, but also with Bluetooth support — thanks to this, you can get by with one adapter instead of two. And in routers and access points, this feature allows external devices to access the Internet (or local area network) over a Bluetooth connection instead of Wi-Fi. This format of work allows you to unload the Wi-Fi channel and reduce the power consumption of connected devices; this is especially important for smart home components and other IoT devices, some routers/access points expressly state that Bluetooth is intended mainly for such electronics. Other ways of using this technology, more specific, may be envisaged; however, this is rare.

— Voice assistant. Device support for a particular voice assistant. The most common options are (individually or together):

• Amazon Alexa
• Google Assistant

The specific functionality of these assistants can be clarified from special sources (especially since it is constantly being optimized and expanded). Here we note that in the case of Wi-Fi equipment, we are usually not talking about an assistant built into the device itself, but about improved compatibility with smartphones and other gadgets that have the corresponding assistant installed. Such functionality can be especially useful given that modern voice assistants are also used to control smart home components. Communication with such control is often carried out just through a home router or other similar equipment, and the support of such equipment for voice assistants greatly simplifies setup and expands the capabilities of the entire system.

— NAT (Network Address Translation). A function that allows Wi-Fi equipment, when working with an external network (for example, the Internet), to replace the IP addresses of all computers and other devices connected to this equipment with one common IP address. In other words, a network with such a router is seen "from the outside" as one device, with one common IP. The most popular use of NAT is to connect several subscribers to the Internet (for example, all computers and gadgets within a home or office) through one provider account. At the same time, the number of such subscribers within the network is limited only by the capabilities of the router and can be freely changed; this will not affect access to the World Wide Web (whereas without using NAT, one would have to organize a separate account for each device). NAT support is a mandatory feature for routers (see "Device type").

— Bridge mode. Possibility of operation of the equipment in the bridge mode. This mode allows you to wirelessly connect individual network segments to each other — for example, to combine two floors if it is difficult to lay a cable between them. However, communication over longer distances is also possible — in some directional access points (see "Device type"), created mainly for just such an application, the range can exceed 20 km. Actually, this mode supports most access points (both directional and conventional), but it is also popular in other types of equipment, in particular, routers.
Note that to work in bridge mode, it is best to use the same type of device — this guarantees high-quality communication in both directions. It is also worth mentioning that in addition to the two-way point-to-point mode, there is also equipment with support for multi-way bridges (“point-to-multipoint”); the availability of such a possibility should be clarified separately.

— Repeater mode. An operating mode in which the equipment only repeats the Wi-Fi signal from another device, playing the role of a repeater. The main function of this function is to expand Wi-Fi networks, providing access where the main device (for example, a router) does not reach. A classic example of repeaters is Wi-Fi amplifiers (see "Device type"), they have this mode by definition; however, it is also found in other types of Wi-Fi equipment. The exception is MESH systems that have similar specifics, but differ in the format of work. See below for more information about this format, but here we note that networks with repeaters are in many ways inferior to MESH in terms of practical capabilities. Firstly, the signals from the main equipment and from the repeater are seen as separate Wi-Fi networks, and when moving between them, subscriber devices must reconnect; this can happen automatically, but disconnections and network changes still cause inconvenience. Secondly, working through a repeater significantly reduces the speed of Wi-Fi. Thirdly, the repeater operates according to a strictly fixed, pre-established routing scheme. On the other hand, access points with a repeater function are much cheaper than MESH nodes, and the mentioned drawbacks are far from always critical.

— MESH mode. Ability to operate the device as a MESH network node. By definition, all MESH systems have this feature, but it can be provided in other types of equipment. A detailed description of networks of this type is given in the paragraph “Device type — MESH system”. Here we will briefly describe their features and the difference between this mode and the repeater mode (see above), which has a largely similar purpose.
MESH technology allows you to create a single wireless network using many separate nodes (access points) connected to each other via Wi-Fi. In this case, the so-called seamless mode of operation is implemented: the entire network is seen as a single whole, switching between access points, if necessary, occurs automatically, in such cases the connection is not broken and the user does not notice the transition to another network node at all. This is one of the key differences from using repeaters. Another difference is dynamic routing: MESH network nodes automatically determine the optimal signal traversal mode. Due to this, as well as due to some other features of this technology, the presence of "intermediaries" on the signal path practically does not affect the communication speed (unlike the same repeaters). The main disadvantage of equipment with this function can be called a relatively high cost.

— Beamforming. A technology that allows you to amplify the Wi-Fi signal in the direction where the receiving device is located (instead of broadcasting this signal in all directions or in a wide sector, as is the case in normal mode). Narrowing the radiation pattern allows you to send more power towards the receiver, thus increasing the range and communication efficiency; while the position of the receiving device is determined automatically, the user does not need to deal with additional settings. And many models of Wi-Fi equipment are capable of amplifying the signal in several directions at once (usually, several antennas are provided for this). At the same time, subscriber devices do not have to support Beamforming — communication improvement is noticeable even with the one-way use of this technology (although not as obvious as with the two-way one).
Also note that the unified Beamforming standards were officially implemented as part of the Wi-Fi 5 specification. However “beamforming” was also used in earlier versions of Wi-Fi, however, different manufacturers used different methods for implementing Beamforming, incompatible with each other. So these days, this feature is almost never found outside of Wi-Fi 5 compatible equipment.

— Firewall. A feature that allows a Wi-Fi device to control traffic passing through it. In fact, the Firewall is a set of software filters: these filters compare data packets with the specified parameters and decide whether or not to pass traffic. In this case, the processing can be carried out according to two rules: “everything that is not expressly prohibited is allowed”, or vice versa, “everything that is not expressly permitted is prohibited”. The main function of a firewall is to protect the network (or individual network segments) from unauthorized access and various attacks. In addition, this function can be used to control user activity — for example, prohibitions on access to certain Internet sites. Note that a firewall can also be implemented at the level of individual devices, but using it on a router allows you to secure the entire network at once.

CLI (Telnet). Ability to control the device via Telnet protocol. This is one of the protocols used today to remotely control network equipment; while Telnet, unlike another popular HTTP standard, does not have a graphical interface and uses only the command line. Such access is used mainly for service purposes — for debugging and changing settings in other text-based protocols (HTTP on web pages, SMTP and POP3 on mail servers, etc.); Telnet requires specialized knowledge.

— WPA. An encryption protocol created as a temporary solution to the most critical vulnerabilities of the WEP described below. It uses a more advanced encryption algorithm, as well as the transmission of passwords in encrypted form. However, the reliability of this standard also turned out to be insufficient, so an improved version, WPA2, was developed.

— WEP. Historically, the first encryption protocol used in wireless networks. It uses encryption from 64-bit to 256-bit, the latter option is considered strong in itself, however, the standard's own vulnerabilities allow a specialist to hack such a communication channel without much difficulty. As a result, WEP is completely obsolete, its support is provided mainly for compatibility with the simplest equipment (especially since it is technically easy to provide this support).

— WPA2. The most popular security standard in modern Wi-Fi equipment. At one time, it became an important update to the original WPA: in particular, the AES CCMP algorithm was introduced into WPA2, which is extremely difficult to crack. Over time, however, some vulnerabilities were identified in this protocol, which led to the development of a more advanced WPA3; however, WPA3 is just beginning to be massively implemented, and in most Wi-Fi devices, WPA2 remains the most advanced standard.
It is worth noting two nuances. First, WPA2 is available in two versions — personal and corporate; in this case, we are talking about pers...onal, corporate options are placed in paragraph "802.1x". Secondly, support for this standard is guaranteed to also be compatible with WEP and original WPA.

— WPA3. A fundamental improvement to WPA2, introduced in 2018, addressing weaknesses identified in WPA2 in the 14 years since it went live. This standard introduced four key innovations:

• Improved security for public networks. Unlike its predecessor, WPA3 encrypts the traffic between the gadget and the router / access point, even if the network is public and does not require a password.
• Protection against the KRACK vulnerability, which allowed hacking the WPA2 communication channel at the time the connection was established. The SAE algorithm is responsible for this protection — more advanced than the previously used PSK. In particular, when establishing a connection via SAE, both devices are considered equal (in PSK, the receiver and transmitter were clearly defined) — this does not allow an attacker to “wedge” between devices using KRACK methods.
• Easy Connect feature — simplifies connection to Wi-Fi networks for devices that do not have displays (in particular, smart home components). Each of these devices will have a QR code on the body, and to connect to the network, it will be enough to scan this code using a smartphone / tablet already connected to this network. However this function is not directly related to WPA3, WPA2 is sufficient for its operation; however, mass adoption of Easy Connect should be expected at the same time as WPA3.
• Improved encryption algorithms for sensitive data, suitable even for government agencies and defense enterprises. However, this feature is relevant mainly for the corporate version of WPA3 — and support for this version is indicated as "802.1x" (see below, in this case we are talking mainly about the personal version of this standard).

In many devices, upgrading from WPA2 to WPA3 can be done in software by installing a new firmware version. However, if support for this protocol is important to you, it is best to choose equipment where such support is initially provided. Also note that the presence of WPA3 is almost guaranteed to also be compatible with WPA2.

— 802.1x. In this case, it implies support for corporate security standards — most often the corresponding versions of the WPA2 protocols, in new devices also WPA3. For example, if the specifications indicate "802.1x" in addition to "WPA3", then this means that this model supports both personal and corporate versions of WPA3. As for the differences between similar versions, one of them is the support for a separate authentication server in corporate protocols. In other words, when using this function, data on accounts and access rights are stored separately from Wi-Fi equipment, on a special secure server, and it is this server that in each case checks the data of the connected equipment and decides whether to allow or deny access.