m)?
ANS: Frequency-Hoping Spread Spectrum (FHSS) receives signals at both ends in synchronous and simultaneous manner. For a non-specific receiver, the jump signal generated by FHSS is only considered impulse noise. The signals deployed by the FHSS can be specially designed to avoid noise or non-repetitive channels of One-to-Many, and these frequency hopping signals must comply with the FCC requirements, using more than 75 frequency hopping signals, and the maximum time interval (Dwell Time) of frequency hopping to the next frequency is 400ms.
Q9: What is Direct Sequence Spread Spectrum?
ANS: Direct Sequence Spread Spectrum (DSSS) uses more than 10 chips to represent "1" or "0" bits, so that the original higher power and narrower frequency becomes a low power frequency with wider frequency. How many chips are used per bit is called Spreading chips. A higher Spreading chips can increase noise interference, while a lower Spreading Ration can increase the number of users.
Basically, Spreading Ration is quite small in DSSS, for example, in almost all 2.4GHz wireless LAN products, there are less than 20 Spreading Ration used. In the IEEE 802.11 standard, the Spreading Ration is only 11, but the FCC stipulates that it must be greater than 10, while in the experiment, the best Spreading Ration is about 100.
Q10: How wide is the coverage that a wireless network can cover?
ANS: The coverage area that a wireless network can cover in general should depend on whether the environment is open or not. If an external antenna is not added, it is about 250M in the view. If it is a semi-open space and a compartment area, it is about 35~50M. Of course, if an external antenna is added, the distance can be further. This depends on the gain of the antenna itself, so it needs to be planned according to the needs of the customer.
Q11: What is the confidentiality of wireless networks during use?
ANS: Basically, GEMPLEX's wireless network technology adopts a DSSS system, which itself has anti-eavesdropping function. In addition, the dual protection of data encryption function (WEP40bits), so its security is quite comprehensive.
Q13: What is a bridge (Access Point)?
ANS: Access Point, commonly known as a network bridge, is used as the bridge between traditional wired LAN and wireless LAN. Therefore, any PC equipped with a wireless network card can share resources of wired LAN or even wide area networks through AP. In addition, the AP itself also has the function of network management, which can be used as necessary control management for PCs connected to wireless network cards.
Q14: How many workstations can Access Point support at the same time?
ANS: In theory, it can support a CLASS C, but in order to make the workstation itself have enough bandwidth to utilize, it is generally recommended that an AP support workstations of about 20 to 30 in the best state.
Q15: What is the Roaming function?
ANS: Just like a big brother, you can roam between different base stations, and wireless network workstations can roam between different APs. As long as the ESSID definition of the AP group is the same, the natural wireless network workstation can roam freely in the areas covered by radio waves.
Q16: If wireless network equipment is installed outdoors, how can it prevent lightning strikes?
ANS: Basically, the wireless network can be equipped with a lightning arrester device. This device can be optionally installed on a wireless network device to facilitate external sudden waves to cause system damage.
Q17: What is Access Control?
ANS: Basically, each wireless network card has a unique set of hardware addresses, the so-called MAC address. Through the Access Control table, some cards can be defined to log in to this AP. Some cards are denied to log in, so that the control mechanism can be achieved, which can prevent non-related personnel from logging into the network at will and stealing resources.
Q18: What is ASBF?
ANS: ASBF (Automatic Scale Back Functionality), this function is a Gemplex AP unique feature, ensuring that WLAN is always at the best online quality. In addition, it also provides wireless network cards that support multiple manufacturers, but their network cards must be designed in compliance with the specifications of IEEE 802.11.
Q19: What is Power Management?
ANS: Since Notebook must be charged after about 2 hours of use, if other peripheral devices are used at the same time, it will definitely consume more power. Therefore, this function is to effectively manage the power consumed by the wireless network card. In other words, it can control the timely timely when there is DATA sending or receiving, it is in "Wake up status" and vice versa.
Q20: Does the length of the wire used by the antenna affect the transmission quality?
ANS: Generally speaking, the length, material, and impedance matching of the wire used by the antenna will have a certain impact on the signal, and the most obvious one is gain attenuation. Usually, the signal attenuation is about 1.2dBi at a length of 20 feet, and the average attenuation of 8dBi will reduce the original transmission distance by about half. Therefore, the length and quality of the wire cannot be ignored in the application of wireless products.
Q21: When erecting directional antennas, are there any tools that provide instructions to optimize the signal quality?
ANS: Gemplex's Bridge itself provides a set of software online quality correction programs, which are presented on the screen in a graphic curve. Users can clearly see the current strength and weakness of the signal, and adjust the position of the antenna, which has reached the best state.
Q22: What is Ad-hoc?
ANS: Constitutes a special wireless network application mode. A group of computers can be connected to each other and share resources without access point.
Q23: What is Infrastructure?
ANS: An application model that integrates wired and wireless LAN architectures. Through this architecture model, the sharing of network resources can be achieved. This application needs to be achieved through Access Point.
Q24: What is BSS?
ANS: A special application of Ad-hoc LAN, called Basic Service Set (BSS). A group of computers can set the same BSS name and form a group of its own, and this BSS name is the so-called BSSID.
Q25: What is ESS?
ANS: An infrastructure application, one or more BSSs can be defined as an Extended Service Set (ESS). Users can roaming and access any information in BSSs on the ESS. Access Points must set the same ESSID and channel to allow roaming.
Q26: What is SNMP?
ANS: "Simple Network Management Protocol" is a network management communication protocol. Through SNMP software, it can be connected to a device that can support SNMP and collect all the information of the device and perform other integrated applications. Gemplex Wireless LAN product has this function.
Q27: What is WEP?
ANS: “Wired Equivalent Protection”, a way to encrypt data. The encryption of WEP 40bits is the standard specification of IEEE 802.11. Through WEP processing, our data can be more secure in transmission.
Application of wireless LAN
Between buildings
Building network connections between buildings replaces dedicated lines, which are simple and cheap.
Catering and retail
The catering service industry can use wireless LAN products, and can directly enter and transmit the content of the customer order to the kitchen and counter. When a retailer promotes, it can use wireless LAN products to set up temporary cash register counters.
Medical
Using a portable computer with wireless LAN products to obtain real-time information, medical staff can avoid delays in treating injuries, unnecessary paper work, delays in document cycles and misdiagnosis, etc., and improve the quality of care for injuries.
enterprise
When employees in an enterprise use wireless LAN products, no matter where they have wireless LAN products in any corner of the office, they can send emails, share files and browse the Internet at will.
Warehousing management
For general warehousing personnel, through the application of wireless networks, the latest information can be entered into the computer warehousing system immediately.
Container distribution yard
The bridge cranes in general container distribution yards can transmit real-time information back to the office when the container is transferred to the container to facilitate the progress of related operations.
Monitoring system
Generally, it is located in a remote location and needs to be monitored on the site. Due to the difficulty of wiring, the remote image can be transmitted back to the main control station through the wireless network.
Exhibition venue
For example, electronics and computer exhibitions, due to the high demand for networks and the wiring will make the venue appear messy, it is a best choice if you can use wireless networks.
DSSS vs FHSS
DSSS
FHSS
Expand frequency characteristics
Use more than 10 chips to represent "1" or "0", so that the original higher power and narrower frequency become low power with wider frequency.
Synchronize and simultaneously accept signals transmitted by specific types of narrow frequency carriers at both ends. For a non-specific reveiver, the jump signal generated by FHSS can only be considered impulse noise to it.
Modulation difference
PSK，DBPSK，DQPSK
GFSK
Anti-noise capability
The DQPSK modulation method of DSSS is composed of linear amplifiers, which has excellent range of action and noise resistance.
FHSS's FSK modulation method is simple and uses a nonlinear power amplifier.
Differences
High Speed
Long Distance
Easy Integration
Suitable for use in more fixed environments
Large range of action
Low Speed
Short Range
Carrier Data Voice
Better Security
The DSSS and FHSS depend on the product's market positioning, because it can solve the transmission capabilities and characteristics of wireless local area networks, including anti-interference capabilities, usage distance range, bandwidth size and transmission data size. DSSS technology is suitable for applications in fixed environments or with high requirements for transmission quality. Therefore, wireless factories, wireless hospitals, and network communities mostly use DSSS wireless technology products. FHSS is mostly used for endpoints that require fast movement, such as mobile phones, and its wireless transmission technology adopts FHSS spreading technology. Article entry: aaadxmm Editor in charge: aaadxmm
ANS: Frequency-Hoping Spread Spectrum (FHSS) receives signals at both ends in synchronous and simultaneous manner. For a non-specific receiver, the jump signal generated by FHSS is only considered impulse noise. The signals deployed by the FHSS can be specially designed to avoid noise or non-repetitive channels of One-to-Many, and these frequency hopping signals must comply with the FCC requirements, using more than 75 frequency hopping signals, and the maximum time interval (Dwell Time) of frequency hopping to the next frequency is 400ms.
Q9: What is Direct Sequence Spread Spectrum?
ANS: Direct Sequence Spread Spectrum (DSSS) uses more than 10 chips to represent "1" or "0" bits, so that the original higher power and narrower frequency becomes a low power frequency with wider frequency. How many chips are used per bit is called Spreading chips. A higher Spreading chips can increase noise interference, while a lower Spreading Ration can increase the number of users.
Basically, Spreading Ration is quite small in DSSS, for example, in almost all 2.4GHz wireless LAN products, there are less than 20 Spreading Ration used. In the IEEE 802.11 standard, the Spreading Ration is only 11, but the FCC stipulates that it must be greater than 10, while in the experiment, the best Spreading Ration is about 100.
Q10: How wide is the coverage that a wireless network can cover?
ANS: The coverage area that a wireless network can cover in general should depend on whether the environment is open or not. If an external antenna is not added, it is about 250M in the view. If it is a semi-open space and a compartment area, it is about 35~50M. Of course, if an external antenna is added, the distance can be further. This depends on the gain of the antenna itself, so it needs to be planned according to the needs of the customer.
Q11: What is the confidentiality of wireless networks during use?
ANS: Basically, GEMPLEX's wireless network technology adopts a DSSS system, which itself has anti-eavesdropping function. In addition, the dual protection of data encryption function (WEP40bits), so its security is quite comprehensive.
Q13: What is a bridge (Access Point)?
ANS: Access Point, commonly known as a network bridge, is used as the bridge between traditional wired LAN and wireless LAN. Therefore, any PC equipped with a wireless network card can share resources of wired LAN or even wide area networks through AP. In addition, the AP itself also has the function of network management, which can be used as necessary control management for PCs connected to wireless network cards.
Q14: How many workstations can Access Point support at the same time?
ANS: In theory, it can support a CLASS C, but in order to make the workstation itself have enough bandwidth to utilize, it is generally recommended that an AP support workstations of about 20 to 30 in the best state.
Q15: What is the Roaming function?
ANS: Just like a big brother, you can roam between different base stations, and wireless network workstations can roam between different APs. As long as the ESSID definition of the AP group is the same, the natural wireless network workstation can roam freely in the areas covered by radio waves.
Q16: If wireless network equipment is installed outdoors, how can it prevent lightning strikes?
ANS: Basically, the wireless network can be equipped with a lightning arrester device. This device can be optionally installed on a wireless network device to facilitate external sudden waves to cause system damage.
Q17: What is Access Control?
ANS: Basically, each wireless network card has a unique set of hardware addresses, the so-called MAC address. Through the Access Control table, some cards can be defined to log in to this AP. Some cards are denied to log in, so that the control mechanism can be achieved, which can prevent non-related personnel from logging into the network at will and stealing resources.
Q18: What is ASBF?
ANS: ASBF (Automatic Scale Back Functionality), this function is a Gemplex AP unique feature, ensuring that WLAN is always at the best online quality. In addition, it also provides wireless network cards that support multiple manufacturers, but their network cards must be designed in compliance with the specifications of IEEE 802.11.
Q19: What is Power Management?
ANS: Since Notebook must be charged after about 2 hours of use, if other peripheral devices are used at the same time, it will definitely consume more power. Therefore, this function is to effectively manage the power consumed by the wireless network card. In other words, it can control the timely timely when there is DATA sending or receiving, it is in "Wake up status" and vice versa.
Q20: Does the length of the wire used by the antenna affect the transmission quality?
ANS: Generally speaking, the length, material, and impedance matching of the wire used by the antenna will have a certain impact on the signal, and the most obvious one is gain attenuation. Usually, the signal attenuation is about 1.2dBi at a length of 20 feet, and the average attenuation of 8dBi will reduce the original transmission distance by about half. Therefore, the length and quality of the wire cannot be ignored in the application of wireless products.
Q21: When erecting directional antennas, are there any tools that provide instructions to optimize the signal quality?
ANS: Gemplex's Bridge itself provides a set of software online quality correction programs, which are presented on the screen in a graphic curve. Users can clearly see the current strength and weakness of the signal, and adjust the position of the antenna, which has reached the best state.
Q22: What is Ad-hoc?
ANS: Constitutes a special wireless network application mode. A group of computers can be connected to each other and share resources without access point.
Q23: What is Infrastructure?
ANS: An application model that integrates wired and wireless LAN architectures. Through this architecture model, the sharing of network resources can be achieved. This application needs to be achieved through Access Point.
Q24: What is BSS?
ANS: A special application of Ad-hoc LAN, called Basic Service Set (BSS). A group of computers can set the same BSS name and form a group of its own, and this BSS name is the so-called BSSID.
Q25: What is ESS?
ANS: An infrastructure application, one or more BSSs can be defined as an Extended Service Set (ESS). Users can roaming and access any information in BSSs on the ESS. Access Points must set the same ESSID and channel to allow roaming.
Q26: What is SNMP?
ANS: "Simple Network Management Protocol" is a network management communication protocol. Through SNMP software, it can be connected to a device that can support SNMP and collect all the information of the device and perform other integrated applications. Gemplex Wireless LAN product has this function.
Q27: What is WEP?
ANS: “Wired Equivalent Protection”, a way to encrypt data. The encryption of WEP 40bits is the standard specification of IEEE 802.11. Through WEP processing, our data can be more secure in transmission.
Application of wireless LAN
Between buildings
Building network connections between buildings replaces dedicated lines, which are simple and cheap.
Catering and retail
The catering service industry can use wireless LAN products, and can directly enter and transmit the content of the customer order to the kitchen and counter. When a retailer promotes, it can use wireless LAN products to set up temporary cash register counters.
Medical
Using a portable computer with wireless LAN products to obtain real-time information, medical staff can avoid delays in treating injuries, unnecessary paper work, delays in document cycles and misdiagnosis, etc., and improve the quality of care for injuries.
enterprise
When employees in an enterprise use wireless LAN products, no matter where they have wireless LAN products in any corner of the office, they can send emails, share files and browse the Internet at will.
Warehousing management
For general warehousing personnel, through the application of wireless networks, the latest information can be entered into the computer warehousing system immediately.
Container distribution yard
The bridge cranes in general container distribution yards can transmit real-time information back to the office when the container is transferred to the container to facilitate the progress of related operations.
Monitoring system
Generally, it is located in a remote location and needs to be monitored on the site. Due to the difficulty of wiring, the remote image can be transmitted back to the main control station through the wireless network.
Exhibition venue
For example, electronics and computer exhibitions, due to the high demand for networks and the wiring will make the venue appear messy, it is a best choice if you can use wireless networks.
DSSS vs FHSS
DSSS
FHSS
Expand frequency characteristics
Use more than 10 chips to represent "1" or "0", so that the original higher power and narrower frequency become low power with wider frequency.
Synchronize and simultaneously accept signals transmitted by specific types of narrow frequency carriers at both ends. For a non-specific reveiver, the jump signal generated by FHSS can only be considered impulse noise to it.
Modulation difference
PSK，DBPSK，DQPSK
GFSK
Anti-noise capability
The DQPSK modulation method of DSSS is composed of linear amplifiers, which has excellent range of action and noise resistance.
FHSS's FSK modulation method is simple and uses a nonlinear power amplifier.
Differences
High Speed
Long Distance
Easy Integration
Suitable for use in more fixed environments
Large range of action
Low Speed
Short Range
Carrier Data Voice
Better Security
The DSSS and FHSS depend on the product's market positioning, because it can solve the transmission capabilities and characteristics of wireless local area networks, including anti-interference capabilities, usage distance range, bandwidth size and transmission data size. DSSS technology is suitable for applications in fixed environments or with high requirements for transmission quality. Therefore, wireless factories, wireless hospitals, and network communities mostly use DSSS wireless technology products. FHSS is mostly used for endpoints that require fast movement, such as mobile phones, and its wireless transmission technology adopts FHSS spreading technology. Article entry: aaadxmm Editor in charge: aaadxmm