distributed antenna system (DAS)

A distributed antenna system (DAS) is a way to deal with isolated spots of poor coverage inside a large building by installing a network of relatively small antennas throughout the building to serve as repeaters.

The antennas are physically connected to a central controller which is connected to the wireless carrier network’s base station. Because distributed antenna systems operate on RF spectrum licensed to wireless carriers, an enterprise cannot undertake a DAS deployment on its own without involving at least one carrier. 

Distributed antenna systems can be passive or active. A passive DAS grabs cellphone signals from antennas on the roof and runs them through leaky feeder cables throughout the building. In this approach, the signal leakage distributes the signal. In an active system, the signal is passed from roof antennas through fiber cables. Along the way, systems boost and amplify signals as needed.

Deployment is the most expensive stage of a DAS project because installing antennas and stringing fiber optical or coaxial cable between antenna modules and the controller are all very labor intensive processes. Generally, the carrier bears the costs of installing the system as well as maintenance expenses and many times, the carrier will only agree to take on these costs if the deployment fits within their network plans, covers a large number of subscribers or fills an significant gap in service. To keep the cost down, a DAS may be shared by multiple carriers.

Distributed antenna systems are transparent to mobile devices, providing both voice and data services to mobile devices just like any tower on a cellular network. Densely populated indoor spaces such as shopping malls, medical centers and high-rise buildings are all good candidates for DAS deployments.

Over the past five years, wireless data traffic has increased more than 20,000 percent on AT&T’s wireless network alone. People are no longer only accessing the Internet at home or in the office, they are doing it wherever they are from their mobile device.

AT&T network engineers are helping enable this shift in Internet usage habits by putting in place new technologies, such as Distributed Antenna Systems (DAS). A DAS network consists of many antennas tuned to precisely match the areas of a building or venue where boosted service is needed. AT&T DAS helps address the exponential network traffic growth at large venues and other hard to serve areas, such as sporting and entertainment venues, hospitals, college campuses, airports, hotels, conference centers and more.

DAS helps boost mobile broadband coverage, improve reliability in heavily trafficked areas and enhance network capacity, alleviating pressure on wireless networks when thousands of people in close proximity are actively using their mobile devices simultaneously. DAS is seamless and invisible for customers, but the results are easy to see. Data and voice capacity more than doubled at the pro sports venues that installed AT&T DAS in 2011.

Behind the scenes making this innovation possible are AT&T engineers implementing a variety of strategies to meet the unique needs of each venue or building owner.

Chad Townes, Vice President of AT&T’s Antenna Solutions Group (ASG), oversees all of the company’s DAS installations. As Towne’s group began to notice smartphone trends and usage patterns skyrocket, increased emphasis was placed on getting ahead of the curve by installing DAS in a variety of locations, including sports venues. As Vice President of AT&T’s ASG, Townes is responsible for the end to end deployment of AT&T wireless infrastructure delivered via DAS. This includes the Sales, Negotiations, RF Engineering, Design, and Construction of both in building and outdoor DAS applications throughout AT&T’s network.

Bill Schlough, Senior Vice President and Chief Information Officer for the San Francisco Giants, sensed mobile data demand was on a sharp rise as early as 2009, which led his charge to create an extremely tech-friendly atmosphere at AT&T Park, home of the San Francisco Giants. Leading up to the 2010 baseball season, Schlough and his team already had an AT&T Wi-Fi system in place, but worked with AT&T to install a DAS to combat the data crunch coming from the nimble hands of smartphone-wielding fans at the ballpark.

Since the installation, the mobile experience at the ballpark has been night and day according to Schlough. While many fans might not know that DAS or Wi-Fi are powering their network at Giants games, they do notice the reliable and consistent mobile Internet connection they have come to trust and rely on to enhance the experience at games.

AT&T is a leader in the DAS space and annually installs hundreds of systems across the country. However, as new technology and opportunities present themselves, AT&T’s ASG will continue to adapt and modify the way its DAS perform and operate in order to provide the best possible end-user experience:

• Faster Speeds. As DAS deployments continue nationwide at sporting stadiums, campuses, airports and other venues, AT&T is beginning to upgrade and build new DAS with ultra-fast 4G LTE speeds.
• DAS on Wheels (DOW). At the recent major political convention in Charlotte, N.C. AT&T rolled out its first ever DAS on Wheels. The mobile DAS consisted of a mobile head end situated in an AT&T truck and portable antennas located throughout a major Charlotte Arena. AT&T is currently exploring future opportunities to deploy DOW.

NETWORK

                                                         

(n.) A network is a group of two or more computer systems linked together. There are many types of computer networks, including:

local-area networks (LANs) : The computers are geographically close together (that is, in the same building).

wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves.

campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base.

metropolitan-area networks MANs): A data network designed for a town or city.

home-area networks (HANs): A network contained within a user's home that connects a person's digital devices.

In addition to these types, the following characteristics are also used to categorize different types of networks:

topology : The geometric arrangement of a computer system. Common topologies include a bus, star, and ring. See the Network topology diagrams in the Quick Reference section of Webopedia.

protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network .

architecture : Networks can be broadly classified as using either apeer-to-peer or client/server architecture.

Computers on a network are sometimes called nodes. Computers and devices that allocate resources for a network are called servers.

(v.) To connect two or more computers together with the ability to communicate with each other.

Common Windows Error Codes and How to Fix them

While working with an operating system, it is not uncommon to encounter errors. Some errors that occur frequently on a Windows system are compiled in a common Windows error codes list. It may not be difficult to fix the common Windows errors but for certain errors, some level of expertise or an in-depth knowledge of the Windows OS may be required. A consolidated list of common windows problems and solutions is useful for a user when they encounter an error. A common Windows error codes list provides a quick and a easy reference and also a possible solution to fix a common Windows error. 

Common Windows Error Codes and How to Fix them!

Below is a list of the most common error codes that you may face while using Windows and its basic components. Some solutions have been provided for you to try to solve them. You should also note that some require the assistance of a computer technician and you should not try to fix them yourself as they could seriously damage your computer system.

• Error #0

Error Message: Connection Successful! 
Solution: Does not require any action.

• Error #2

Error Message: System cannot find specified file 
Solution: You should reinstall NCP & DUN

• Error #5

Error Message: Access Denied 
Solution: 
1. Ensure that you have entered the right username and password in the field labeled "domain" for NT/2k 
2. Check that the option "accept any authentication including clear text" is activated

• Error #5

Error Message: Invalid Procedure Call 
Solution: Dialup and Network components must be installed again

• Error #6

Error Message: Stack Overflow 
Solution: 
1. Try cold booting your computer 
2. If this does not work, the problem might come from your RAM or the Swap file

• Error #20

Error Message: The system cannot find the specified device 
Solution: 
1. Ensure that the right modem has been selected 
2. If it does not respond, try to reinstall it 
3. You can also try to reinstall NCP/DUN/RAS

• Error #71

Error Message: No more connections are allowed 
Solution: 
1. Someone else might have connected under your account 
2. If you have been ghosted on the server, your Internet Service Provider can bump the ghost program off

• Error #380

Error Message: Invalid Proper Value 
Solution: 
1. Autodial should be pointed to the correct dialler 
2. Else, set up the dialler again

• Error #600

Error Message: An operation is pending 
Solution: 
1. You should first try rebooting your computer 
2. Ensure that no other program is using your modem 
3. Else, press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem 
4. Make sure that your computer is Spyware free

• Error #601

Error Message: The port handle is invalid 
Solution: 
1. Select the modem's COM port and under the Diagnosis section, open "More Info". You should reboot your computer if you are able to get ATI responses, remove the erroneous init string or enter ATZ as the init 
2. You can also reinstall your modem 
3. Else press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem 
4. Your Dialup Networking should be reinstalled together with its components 
5. Your modem might not be working properly. You should then consult your computer manufacturer

• Error #602

Error Message: The port is already open 
Solution: 
1. Try to reboot your computer 
2. Ensure that no other program is using the modem 
3. Else press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem 
4. Try uninstalling the AOL Adapters in the Network Control panel and reboot your computer. Install your Dialup Adapter again 
5. Remove the erroneous init string or enter ATZ as the init 
6. If you have Quicken 2000, deactivate the Quicken Download Manager 
7. Try installing your modem again 
8. Make sure that your computer is Spyware free

• Error #603

Error Message: Caller's buffer is too small 
Solution: 
1. Ensure that your port is not configured to a low speed 
2. In your "Port Settings", ensure that FIFO is not set to low 
3. Try reinstalling your Dialup Networking together with its components 
4. If you are still having problems, contact your computer manufacturer

• Error #604

Error Message: Wrong information specified. 
Solution: 
1. Ensure that the are no outages in your area 
2. Try to enter the username and password again 
3. Set up the dialler again 
4. Your Dialup Networking should be installed again together with its components 
5. You can also try to reinstall your modem

• Error #605

Error Message: Cannot set port information. 
Solution: 
1. Ensure that the are no outages in your area 
2. Try to enter the username and password again 
3. Set up the dialler again 
4. Your Dialup Networking should be installed again together with its components 
5. You can also try to reinstall your modem

• Error #606

Error Message: The port is not connected. 
Solution: 
1. Select the modem's COM port and under the Diagnosis section, open "More Info". You should reboot your computer if you are able to get ATI responses, remove the erroneous init string or enter ATZ as the init 
2. You can also reinstall your modem 
3. Else, press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem 
4. Your modem might not be working properly. You should then consult your computer manufacturer if the problem persists.

• Error #607

Error Message: The event is invalid. 
Solution: 
1. If this problem arises while dialling up to the internet, verify that the settings of the event log have been correctly set 
2. Try rebooting your system and ensure that the dialler/network settings have been correctly configured 
3. Else, install RAS/DUN again

• Error #608

Error Message: The device does not exist. 
Solution: 
1. Check that the right modem is set in the dialler 
2. Ensure that you are using the right modem drivers by checking the modem diagnostics. If it's not the case, set up the correct drivers. 
3. Reinstall the dialler 
4. Your modem might not be working properly. Try reinstalling it 
5. You should consult your computer manufacturer if the problem persists

• Error #609

Error Message: The device type does not exist. 
Solution: 
1. Check that the right modem is selected in the dialler 
2. Ensure that you are using the right modem drivers by checking the modem diagnostics. If it's not the case, set up the correct drivers 
3. Your modem might not be working properly. Try reinstalling it 
4. You should consult your computer manufacturer if the problem persists

• Error #610

Error Message: The buffer is invalid. 
Solution: 
1. Ensure that your port speed is set to low in the modem properties 
2. In your "Port Settings", check that FIFO is not set to low 
3. Reinstall the dialer again 
4. Else, reinstall RAS/DUN 
5. You should consult your computer manufacturer if the problem persists

• Error #611

Error Message: The route is not available. 
Solution: 
1. Try to reboot your computer 
2. Ensure that you set the right configurations for the dialer and network settings 
3. Else, install the network components again 
4. If you are using a LAN connection, consult your system administrator

• Error #612

Error Message: The route is not allocated. 
Solution: 
1. Reboot your computer 
2. Ensure that you set the right configurations for the dialler and network settings

• Error #613

Error Message: Invalid compression specified. 
Solution: 
1. Try to reboot your computer 
2. Else, add &K3 to the extra settings. 
3. If this still does not solve the problem, add &K3 
4. You can also try to reinstall the modem

• Error #614

Error Message: Out of buffers. 
Solution: 
1. Ensure that our port speed is not too low 
2. Try to install your modem again

• Error #615

Error Message: The port was not found. 
Solution: Try to install your modem drivers

• Error #616

Error Message: An asynchronous request is pending. 
Solution: 
1. Reboot your computer 
2. Try to install your modem drivers again

• Error #617

Error Message: The port or device is already disconnecting 
Solution: 
1. Wait until your modem disconnects properly 
2. If this operation is taking too long, reboot your computer

• Error #618

Error Message: The port is not open. 
Solution: 
1. Reboot your computer 
2. Ensure that no other program is making use of the modem

• Error #619

Error Message: The port is disconnected. 
Solution: 
1. Reboot your computer 
2. Ensure that no other program is making use of the modem

• Error #621

Error Message: Cannot open the phone book file. 
Solution: Install Blue Frog connection software again

• Error #622

Error Message: Cannot load the phone book file. 
Solution: Install Blue Frog connection software again

• Error #623

Error Message: Cannot find the book entry. 
Solution: Install Blue Frog connection software again

• Error #626

Error Message: Cannot load a string 
Solution: 
1. Try to reboot your system 
2. Install Blue Frog connection software again

• Error #627

Error Message: Cannot find key 
Solution: Install Blue Frog connection software again

• Error #628

Error Message: The port was disconnected 
Solution: 
1. Install Blue Frog connection software again 
2. Try to install your modem drivers again

• Error #629

Error Message: The port was disconnected by the remote machine. 
Solution: 
1. Install Blue Frog connection software again 
2. Try to enter an alternate Access Number 
3. Try to install your modem drivers again

• Error #630

Error Message: The port was disconnected due to hardware failure. 
Solution: 
1. Install Blue Frog connection software again 
2. Try to reinstall your modem drivers 
3. Try to use an alternate modem 
4. Else, replace your current modem with a new one

• Error #631

Error Message: The port was disconnected by the user. 
Solution: 
1. Ensure that the right Access Number is being dialled 
2. Try to reboot your computer

• Error #632

Error Message: The structure size is incorrect. 
Solution: 
1. Try to reboot your computer 
2. Install Blue Frog connection software again

• Error #633

Error Message: The port is already in use or is not configured for Remote Access dialout. 
Solution: 
1. Try to reboot your computer 
2. Else, try to reinstall your modem drivers

• Error #634

Error Message: Cannot register your computer on the remote network. 
Solution: 
1. Try to check your network settings and modify your computer name 
2. Install the network control panel again

• Error #635

Error Message: Unknown Error 
Solution: 
1. Try to reboot your computer 
2. Install Blue Frog connection software again 
3. Else try to reinstall your modem drivers

• Error #636

Error Message: The wrong device is attached to the port 
Solution: Check in your settings if you have chosen the right modem

• Error #637

Error Message: The string could not be converted 
Solution: 
1. Try to reboot your computer 
2. Install Blue Frog connection software again

• Error #638

Error Message: The request has timed out. 
Solution: 
1. Try to reboot your computer 
2. Install Blue Frog connection software again

• Error #645

Error Message: Internal authentication error. 
Solution: 
1. Try to reboot your computer 
2. Install Blue Frog connection software again 
3. Else, try to reinstall your modem drivers

• Error #650

Error Message: The Remote Access server is not responding. 
Solution: 
1. Check that your connection and network settings have correctly been configured 
2. Ensure that the modem has been correctly set up and look for updated drivers 
3. Set FIFO buffers to a lower speed and ensure that you have unchecked the option "Only connect at this speed"

• Error #676

Error Message: The line is busy 
Solution: Ensure that your Access Number is still active and is correctly dialled

• Error #678

Error Message: There is no answer. 
Solution: 
1. First of all check that your phone lines are correctly plugged in 
2. Ensure that the Access Number is correct 
3. Else, try another Access number 
4. If you are trying to make use of your connection in a bad weather, this might be the source of the problem. Wait until it calms down and try again 
5. Else, install your modem drivers again 
6. If the problem persists, you might need to contact your ISP

• Error #680

Error Message: There is no dial tone. 
Solution: 
1. First of all check that your phone lines are correctly plugged in 
2. The cables might be damaged. Replace them and try again 
3. Else, install your modem drivers again 
4. If the problem persists, you might need to contact your ISP or a technician

• Error #691

Error Message: Access denied because username and/or password is invalid on the domain. 
Solution: 
1. Ensure that you have entered the right username and password 
2. Make sure that your account is active and turned on 
3. You might also try to enter another Access Number 
4. If the problem persists, you might need to contact your ISP

• Error #692

Error Message: Hardware failure in port or attached device. 
Solution: 
1. Browse for and remove any Blue Frog init strings 
2. Install Blue Frog connection software again 
3. Else, install your modem drivers again

• Error #718

Error Message: PPP Timeout 
Solution: 
1. Try to reboot your computer 
2. Ensure that you have entered the right username and password 
3. You might try another Access Number 
4. Install Blue Frog connection software again 
5. Else, install your modem drivers again

• Error #721

Error Message: Remote PPP peer is not responding. 
Solution: For Windows 2000/XP/Vista operating systems, ensure that the security setting for the dialler reads "Allow unsecured Password"

• Error #734

Error Message: The PPP link control protocol terminated. 
Solution: For Windows 2000/XP/Vista operating systems, ensure that the security setting for the dialer reads "Allow unsecured Password"

• Error #777

Error Message: The connection attempt failed because the modem on the remote computer is out of order. 
Solution: 
1. Install Blue Frog connection software again 
2. Install your modem drivers again 
3. Else, install a new modem

• Error #778

Error Message: It was not possible to verify the identity of the server. 
Solution: 
1. Ensure that you are dialling the correct phone number 
2. Verify the connection and Network settings 
3. Ensure that you do not have an outage on the phone line 
4. Ensure that you have correctly installed your modem and check for updated drivers 
5. Set FIFO buffers to a lower speed and ensure that you have unchecked the option "Only connect at this speed"

• Error #779

Error Message: To dial out using this connection, you must use a smart card. 
Solution: 
1. Ensure that all authorisation is allowed in your connection settings in the Security section 
2. Verify that you have correctly set the other dialler settings 
3. Else, create the dialler again 
4. You might need to use the Smart Card Reader as initially setup by the Network Administrator

• Error #780

Error Message: An attempted function is not valid for this connection. 
Solution: Ensure that the dialler, not the one set up for LAN use though, has been properly installed and has the right settings

• Error #781

Error Message: The encryption attempt failed because no valid certificate was found. 
Solution: You have to get a valid certificate by registering to the website http://windows.microsoft.com/... 

Note: The solution for the following problems is already provided in the error messages. If you are still facing problems with them, either contact your ISP or a technician to fix the problem.

• Error #782

Error Message: Network Address Translation (NAT) is currently installed as a routing protocol, and must be removed before enabling Internet Connection Sharing

• Error #783

Error Message: Internet Connection Sharing cannot be enabled. The LAN connection selected as the private network is either not present, or is disconnected from the network. Please ensure that the LAN adapter is connected before enabling Internet Connection Sharing.

• Error #784

Error Message: You cannot dial using this connection at logon time, because it is configured to use a user name different than the one on the smart card. If you want to use it at logon time, you must configure it to use the user name on the smart card.

• Error #785

Error Message: You cannot dial using this connection at logon time, because it is not configured to use a smart card. If you want to use it at logon time, you must edit the properties of this connection so that it uses a smart card.

• Error #786

Error Message: The L2TP connection attempt failed because there is no valid machine certificate on your computer for security authentication.

• Error #787

Error Message: The L2TP connection attempt failed because the security layer could not authenticate the remote computer.

• Error #788

Error Message: The L2TP connection attempt failed because the security layer could not negotiate compatible parameters with the remote computer.

• Error #789

Error Message: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

• Error #790

Error Message: The L2TP connection attempt failed because certificate validation on the remote computer failed.

• Error #791

Error Message: The L2TP connection attempt failed because security policy for the connection was not found.

• Error #792

Error Message: The L2TP connection attempt failed because security negotiation timed out.

• Error #793

Error Message: The L2TP connection attempt failed because an error occurred while negotiating security.

• Error #794

Error Message: The Framed Protocol RADIUS attribute for this user is not PPP.

• Error #795

Error Message: The Tunnel Type RADIUS attribute for this user is not correct.

• Error #796

Error Message: The Service Type RADIUS attribute for this user is neither Framed nor Callback Framed.

• Error #797

Error Message: A connection to the remote computer could not be established because the modem was not found or was busy.

• Error #798

Error Message: A certificate could not be found that can be used with this Extensible Authentication Protocol.

• Error #799

Error Message: Internet Connection Sharing (ICS) cannot be enabled due to an IP address conflict on the network. ICS requires the host be configured to use 192.168.0.1. Please ensure that no other client on the network is configured to use 192.168.0.1

• Error #800

Error Message: Unable to establish the VPN connection. The VPN server may be un-reachable, or security parameters may not be configured properly for this connection. 
Solution: 
1. Check your ADSL line as it is probably not synchronized 
2. Verify that your Security Options are correctly set in your connection options 
3. Either your Network Card or your modem might not work properly. Contact a technician if the problem persists

• Error #995

Error Message: Operation aborted.

• Error #1382

Error Message: Maximum length exceeded.

• Error #1793

Error Message: Account expired.

• Error #2250

Error Message: Network connection does not exist.