The following is an example of a TCP/IP address:

BINARY FORMAT

 DECIMAL FORMAT

10000011.01101011.00010000.11001000

 131.107.16.200

Classes of IP addresses:

IP addresses are divided into five classes: A, B, C, D, and E. These classes define the number of bits that can be used for the network ID and the host ID of each address. Class A, B, and C IP addresses are used for assignment to TCP/IP hosts.

Class A: In a Class A IP address, the first octet of the IP address is always between 0 and 127 and represents the network ID, and the remaining three octets are used to represent the unique host ID on the network. There are a maximum of 128 Class A network numbers, and each number is capable of supporting 16,777,214 unique hosts. In this type of IP addresses; the first and the last network numbers are reserved. Hence, there are potentially 126 Class A networks and the actual range of the first octet is always between 1 and 126. In a class A IP address, the highest order binary bit (the leftmost bit of the 32-bit binary number) is always 0.

Class B: If the first octet of an IP address is between 128 and 191, it is a Class B IP address. In a Class B IP address, the first two octets (starting from the left) are used to represent the network numbers and the remaining two represent the unique host ID on the network. An example of a Class B IP address is 167.20.91.203 where 167.20 is the network number and 91.203 is the host ID. There are 16,384 Class B networks and each network can support a maximum of 65,534 unique hosts. In a Class B address, the two leftmost binary bits are always 10.

Class C: If the first octet of an IP address is between 192 and 223, it is a Class C IP address. In a Class C IP address, the first three octets (starting from the left) are used to represent the network numbers and the remaining octet stands for representing the unique host. An example of a Class C IP address is 192.168.1.2 where 192.168.1 is the network number and the host ID is 2. Therefore, there are 2,097,152 Class C network numbers and each network can support a maximum of 254 unique hosts. In a Class C address, the three leftmost binary bits are always 110.

Class D: If the first octet of an IP address is between 224 and 239, it is a Class D address. Class D addresses are used for multicasting to a group of IP hosts and are not assigned to individual devices on a TCP/IP network. In a Class D IP address, the four leftmost binary bits are always 1110.

Class E: If the first octet of an IP address is in the range of 240-255, it is a Class E address. Like Class D addresses, Class E addresses also cannot be assigned to individual devices on a TCP/IP network. Instead, they are reserved for experimental and future use. In a Class E address, the four leftmost binary bits are always 1111.

Loopback addresses: Loopback addresses are IP addresses with 127 in their first octet. These addresses are used to test TCP/IP configuration and hence cannot be used for assignment to individual hosts on a TCP/IP network. The most frequently used loopback address is 127.0.0.1.

IP address table:

Class

 1st Octet Range

 Network ID

 Host ID

 Number of networks

 Number of Host ID’s per network

 Assignable to Hosts?

A

 1-126

 w

 x.y.z

 126

 16,777,214

 Yes

B

 128-191

 w.x

 y.z

 16,392

 65,534

 Yes

C

 192-223

 w.x.y

 z

 2,097,150

 254

 Yes

D

 224-239

 N/A

 N/A

 N/A

 N/A

 No

E

 240-255

 N/A

 N/A

 N/A

 N/A

 No

Loopback

 127

 N/A

 N/A

 N/A

 N/A

 No

Note: w, x, y, or z represents an octet of an IP address.

There are some rules about valid IP addresses, which are described as follows:

The first octet of an IP address must fall within the following ranges:

1-126

128-191

192-223

A valid IP address cannot start with 0, 127, or 224-255.

The host ID of the IP address cannot be all binary 0s or 1s.

The decimal value of any octet in an IP address cannot be greater than 255.

An IP address cannot be greater than 255.

Subnet Masks: Network IDs and host IDs within an IP address are distinguished by using a subnet mask. It tells a TCP/IP host how to interpret IP addresses by defining what portion of IP address is network ID and what portion is host ID. A subnet mask uses consecutive bit groups of all 0s or 1s. All 1s identify the network ID and all 0s identify the host ID portions of an IP address. Hence, a 255 in a subnet mask indicates that the corresponding octet in an IP address is a part of a network number. On the other hand, a 0 in a subnet mask indicates that the corresponding octet in the IP address is a part of the host ID.

For example, the following is an example of a 32-bit subnet mask used with the IP address 131.107.16.200:

11111111.11111111.00000000.00000000

By analyzing this subnet mask, one can know the IP address Class. As in the above example, we can see that there are sixteen 1s and sixteen 0s, which indicates that the IP address belongs to the Class B network.

IP address class

 Default subnet mask (in decimal)

 Default subnet mask (in binary)

Class A

 255.0.0.0

 11111111.00000000.00000000.00000000

Class B

 255.255.0.0

 11111111.11111111.00000000.00000000

Class C

 255.255.255.0

 11111111.11111111.11111111.00000000

Subnet masks are used by hosts to determine their network numbers and to know whether the destination host is on the same network or on a different network. Subnet masks are referenced in either dotted notation or Classless Inter Domain Routing (CIDR) notation. CIDR notation notes the number of binary 1s in the subnet mask. This number is placed at the end of the network ID.

An example of a CIDR notation for Class B IP addresses is shown as follows:

Network ID

Subnet Mask

CIDR Notation

192.168.1.0

255.255.255.0

192.168.1.0/24

172.16.0.0

255.255.0.0

172.16.0.0/16

In the above example of subnet mask (in the CIDR Notation column), the value of 24 refers to 24 binary 1 bits in the subnet mask. Since, in the subnet mask, there are three 255s and each value of 255 represents 8 bits, there are 8*3=24 binary 1 bits in the mask.

Subnetting an IP network number:

Subnetting is a process of subdividing a single IP network into multiple smaller networks with unique subnetted network IDs in order to reduce the size of the broadcast domain and better utilize the bits in the host ID. It is accomplished by modifying the subnet mask values. Subnetted network IDs are created by using bits from the host ID of the original class-based network ID.

Example 1:

A class B network of 139.12.0.0 can have up to 65,534 nodes. Due to a large number of nodes, the broadcast domain is very large. In this situation, subnetting is performed to make the broadcast domain smaller. Network 139.12.0.0 is subnetted by utilizing the first 8 host bits (the third octet) for the new subnetted network ID. When 139.12.0.0 is subnetted, separate networks with their own subnetted network IDs (139.12.1.0, 139.12.2.0, 139.12.3.0) are created.

Example 2:

If a subnet mask of 255.255.255.0 is applied to a Class B IP address of 174.15.0.0, the first three bytes (as is clear from the subnet mask) are represent a network ID, and only the rightmost byte is interpreted as a host ID. Although the address belongs to Class B, subnetting the third byte now can be used to define several subnetworks or subnets. Therefore, the broadcast domain will become smaller and each subnet will support fewer host IDs.

About the Author:

uCertify was formed in 1996 with an aim to offer high quality educational training software and services in the field of information technology to its customers. uCertify provides exam preparation solutions for the certification exams of Microsoft, CIW, CompTIA, Oracle, Sun and other leading IT vendors. To know more about uCertify, please visit http://www.ucertify.com/

This article discusses how the GPS clock can be used to provide an accurate timing reference for computers and computer networks. The GPS system is often used for computer timing applications, such as NTP time servers and accurate timing references.

GPS Time

GPS time is continuously broadcast by the GPS system. Time is referenced to UTC (Universal Coordinated Time), which is the same worldwide and does not vary with time zones. GPS timing information can be received with relatively low-cost equipment, such as a GPS receiver and antenna.

The GPS signal is very weak low-power radio signal. The signal has two designated frequencies, L1 and L2. Frequency, L1, is the civilian GPS frequency transmitted at 1575.42 MHz. The signal travels in a straight line and can pass through clouds, glass and plastics but is blocked by objects such as metal and brickwork. The ideal location for a GPS antenna is therefore on rooftop with a good view of the sky. Often, antenna installation on the side of a building or in a window can provide a good enough view of the sky to give adequate results.

GPS Clock

The GPS system provides a free-to-air time synchronisation service; there are no on-going set-up or subscription charges. Many computer systems utilise the GPS clock as an accurate timing reference. Highly accurate NTP server systems use the GPS clock as an external reference to synchronise Network Time Protocol servers. Typically, a GPS receiver can provide timing information to within a few nanoseconds of UTC. The accuracy achieved with a GPS receiver is generally more than required for most computer network timing applications.

GPS Receiver Output

The GPS receiver constantly outputs position and timing information. Generally, information is transmitted to and from the receiver via a RS232 serial interface. Standard GPS interface protocols exist, the most common being NMEA. The NMEA protocol consists of a number of sentences, or character strings, transmitted at 4800 bits per second. Contained within each character string is accurate time and position information. Due to the latencies involved in serial communication, the NMEA sentences are not generally accurate enough to provide a timing reference. Therefore a pulse per second (PPS) output is utilised. A PPS output is an accurate pulse output each second that is aligned to the start of each second. The PPS output can be fed into a control line on the RS232 interface to provide a hardware interrupt input for accurate timing. Often the DCD RS232 line is utilised as a PPS input from the GPS receiver. The PPS output combined with NMEA timing and positioning information provides a highly accurate timing reference for computers.

GPS Antennas

The GPS antenna is a signal amplifier that boosts the GPS signal for transmission along a cable, usually coax, to the receiver. GPS antennas used for timing purposes are generally dome-shaped pole mounting devices for permanent installation in a static location. Typically, the GPS antenna is fairly small in size, measuring less than 900 mm in diameter

GPS Cabling

The cable distance that can be utilised by a GPS antenna and receiver depends on the amplification of the GPS antenna and the quality of coax used in the installation. A typical GPS antenna may have a gain of 35 db. Low-quality coax such as RG58 has an attenuation of 0.64 db/m at 1575 MHz. Therefore, a cable run of 55m can be obtained using RG58 cable. Higher quality coax, such as LMR400, an unaided cable run of 200m can be achieved. However, very high quality coax can be expensive. A good compromise is LMR200 cable, which can be run unaided to 80m. Longer distances can be achieved with the aid of GPS amplifiers, which amplify the GPS signal still further, to increase cable distance.

“A video is more than thousands of words!” How to make a video tutorial of your website? Use a camera to record their menus? Maybe it’s not a so bad choice! But a camera face to your computer is not the best way to show your website with the following 3 reasons.

1. The camera can not record the screen clearly.

2. You can not edit the video by adding some instructions or narrations easily.

3. The video file is too big for web sharing and transmission.

Maybe you need an application to record your screen, not a camera! Screen recording software helps you to record the screen to mirror all of your operations by recording mouse movements and keystrokes with the screenshots. Even you can add some tips to highlight the important functions. Furthermore, you can add narration from microphone easily to enhance the tutorial. At last you can publish the flash movie and transmit to the technical guys. As you know, the flash format has smaller size and better for network transmission.

The following is a step-by-step guide of how to create a video tutorial of MS Outlook by recording the computer screen in minutes. Or you can click to view the samples now:

http://www.sameshow.com/samples/outlook-tutorial/outlook-tutorial.html

1. Setting the capture mode and record

There are 3 capture modes to be selected: Application region, Custom region and Full screen. Now we select application region to record the Microsoft Outlook, guide others how to create an account in Microsoft Outlook. Click “Record” button to start recording.

Application Region: Capture the window of the specific application that is running.

Custom Region: Capture a customized rectangular shape on your desktop.

Full Screen: Capture the entire screen.

2. Edit and Enhance the tutorial

Once the recording is finished. DemoCreator will import the slides automatically. You can easily to add some interactive elements to the tutorial by slide. Insert new slide or delete unwanted slide. Or add some callouts, notes, animations to the tutorial to make the tutorial more interactive and animated.

Picture URL: http://www.sameshow.com/images/democreator/tutorial/1/edit.gif

3. Add sound to the tutorial

Click “Audio” button and login the Audio Timeline Editor. You can edit the audio easily by cutting, inserting and deleting. And also you can view the slide at the same time when editing the audio. Furthermore, you can record the sound when recording the screen.

Picture URL: http://www.sameshow.com/images/democreator/tutorial/1/sound.gif

4. Publish the flash movie

Click “Publish” button and login the publish menu. Select publish to SWF, LMS, auto-run CD, standalone EXE, or Email. As you know, flash file has the smaller size and safer in network transmission.

Learn more from: http://www.sameshow.com/demo-creator.html

View the created outlook tutorial from: http://www.sameshow.com/democreator/create-software-demo-samples.html

Windows 2003 Server Configuration

Windows 2003 has expanded on the original Windows 2000 time service by providing a true NTP implementation. The time service, installed by default, can synchronise to a NTP Server. Indeed, by manipulating registry settings for the service it can act as both an NTP server and client to synchronise other network clients in the domain.

The ‘Windows Time’ service should be present in the systems service list. The application executable is ‘w32time.exe’. The parameter list for w32time can be found in the registry at:

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32Time

Before modifying registry entries it is good a dood idea to backup the registry settings. The registry can then be restored in the event of problems being encountered.

To configure a Windows 2003 machine to synchronise to an external NTP server, edit the following registry entries:

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeConfigAnnounceFlags

  Set the ?Announce Flags? registry entry to 5, to indicate a reliable time source.

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPClientSpecialPollInterval

  The ?Special Poll Interval? registry entry defines the period in seconds that the Windows 2003 machine should poll the NTP server. A recommended value is 900 seconds, which equates to every 15 minutes.

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersNtpServer

  The ?NTP Server? parameter is used to provide a list of IP addresses or DNS names, separated by a space, of NTP servers that the Windows 2003 machine can synchronise to.

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPServerEnabled

  Changing the ?Enabled? flag to the value 1 enables the NTP Server.

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersType

  Change the server type to NTP by specifying ?NTP? in the ?Type? registry entry.

Windows 2000 Time Service Configuration

Windows 2000 has an integrated time synchronisation service, installed by default, which can synchronise to a NTP Server. Indeed, by manipulating registry settings, the service can act as both an SNTP client and SNTP server to synchronise other network clients.

Before modifying registry entries it is good a dood idea to backup the registry settings. The registry can then be restored in the event of problems being encountered.

The ‘Windows Time’ service should be present in the systems service list. The application executable is ‘w32time.exe’. The parameter list for w32time can be found in the registry at:

  HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParameters

Windows 2000 can operate as an NTP client and synchronise to an NTP server by setting parameter ‘NTP Server’ to the IP address of a NTP Server.

By default, the Microsoft Windows 2000 machine will synchronise to the specified NTP time server every 8 hours (or 3 times a day), which may not be enough to maintain accurate synchronisation. The period can be reduced by setting the ‘Period’ parameter to how many times a day synchronisation is required. Setting the period to 48 will activate synchronisation with the NTP server once every half hour.

Windows 2000 can also be configured to act as an NTP server by setting the ‘Local NTP’ parameter to ’1′.

After editing any of the registry entries for the windows time service, the service must be restarted for the settings to take effect. The services can be started or stopped from the service control applet in ‘administrative tools’. Alternatively the service can be controlled via the DOS net command thus:

  net start w32time

  net stop w32time

NTP Troubleshooting

A number of problems can be encountered when configuring the Windows Time Service. NTP operates using the UDP protocol over TCP/IP. Therefore the TCP/IP network infrastructure must be operational for NTP to be effective. Synchronisation issues may arise when NTP attempts to synchronise to an inaccurate time reference or if network delays are excessive.

Synchronising Time on Network Devices

As well as synchronising Microsoft Windows servers and workstations, NTP can also be used to synchronise network devices, such as hubs, switches and routers. Any network device that can synchronise to a NTP server can be pointed to the Windows server to achieve time synchronisation. In this way the whole network and accompanying infrastructure can be synchronised.

Writen By : Dave Evans

Dave Evans is involved in the development of NTP Server synchronisation solutions to ensure accurate time on PC?s and computer systems. Dave has developed dedicated NTP server systems, NTP synchronised digital clock systems and atomic clock time synchronisation products. Click here to find out more about NTP Server Systems.

Anytime you are dealing with something as sensitive and as important as your computer then you always want to make sure that you know what you are looking for. Well sometimes believe it or not your computer requires a tune up and a maintenance to run properly. Just like you would not let your car run on the same oil that you purchased it with; well your computer needs to be cleaned out and some of the clutter needs to be removed so it can function properly.

If you are noticing that your computer keeps crashing and freezing up; it is time to find out how to choose the right computer diagnostic software. This just means that you want to find the right tool that will help you analyze why your computer is acting the way it is.

You will not need to be a computer techie or be a mechanic to be able to fix your computer. Heck most of the time you will not have to do anything except press “start” and the technology that we have available to us today will take care of your problem. Your job is just to find a reputable “registry cleaner” that will be able to declutter your PC safely and that will walk you through the entire process.

If your computer is not performing at its fastest speed or seems to keep freezing and crashing all the time; then there is something internally wrong with it. You can easily scan your PC online for free and the online scan will inform you what is wrong with your computer. Once you discover that the computer requires to be cleaned and decluttered you can easily pay a small one time fee to get the internal parts of your machine working properly.

Once you clean the registry which is the most important part of your computer; you will notice a huge difference in the way it operates. When deciding which registry cleaner to choose; it is best to choose one that has great customer service. If you have never cleaned up your computer before; you may have some questions. You want to make sure that you can talk to a live person; and not just an automated machine.

If you found this article on “how to choose the right computer diagnostic software” helpful; visit our site below. You can easily scan your computer for free. If it does need to be cleaned then the site will walk you through step by step on the entire process. The process is not complicated and you will not have to worry about whether you are knowledgeable enough or not. All you do is follow the steps and the system will take care of itself.

Computer Diagnostic Software! Free Computer Scan To Check For Invalid Files And System Reference.

Prevent Your Computer From Experiencing PC Errors, Constant Crashes And General System Slowdowns!

The things which a buyer’s guide tell us about buying computer parts can help us a lot. These guides can help us with the current price of the various products and parts, the availability and usefulness of the computer parts, the advantage and disadvantage of buying and using a particular part, etc.

Let us now look at the things the buyer’s guide tells. The buyer’s guides are actually provided by the manufacturing companies, in order to enlighten the users about the features of the parts and about connecting tips. A new user is not likely to know the details of connecting a particular part. That is the justification for providing a user’s guide with the parts. They provide us step by step direction and thus save time, too much effort and energy from being wasted.

These guides are very helpful to the new buyers to take decisions regarding the purchase of the parts. Sometimes it happens that some buyers like to go for assembled parts rather than buying a branded whole computer. In this the benefit is that much money can be saved.

Several brands can be assembled together and can be given a complete form. In this process the advantages are many but if the buyer is not aware of the connecting techniques of the parts then it will be a great problem for him. Under such conditions the buyer’s guide is really very helpful and valuable as a reference text for future.

It is very important to have solid knowledge about the different computer parts and their prices because there are several brands in the market out of which the buyer will find it extremely difficult to choose one. If this knowledge is absent the buyers will not be able to compare the prices. Under such conditions, the buyer’s guide for buying computer parts can give invaluable help. It will in fact show the right path to the buyers.

Sometimes it happens that certain false and duplicate things are also being sold and bought in the market about which people know nothing and thus get deceived. To prevent such practices, several steps have been recommended among which the buyer’s guide is a good one.

Thus we find that when you intend to but a new computer or new computer parts, the buyer’s guide can be of immense help to you. It can be viewed as the ideal companion for the buyer.

Written By : Victor Epand

Victor Epand is an expert consultant for computers, laptops and software. When shopping for used computers, used laptops and used software, we recommend you shop at only the best online stores for used computer parts, used laptop parts.

Creating your own NTP time server is relatively straightforward and if you are a resident of the US then the simplest way is to use a relatively cheap receiver module, set to receive the WWVB timing signal which is broadcast by NIST (National Institute of Standards and Time) at a frequency of 60 kHz.

To create your own product using the WWVB time signal, WWVB receiver modules, are readily available at low cost. When looking for a receiver module there are several points to consider:

There should be a simple interface to allow easy integration of accurate timekeeping into electronic equipment etc. The receiver should use dedicated chips designed specifically to receive the WWVB (USA) time signal. The advantage of these over other solutions is that the modules include the necessary support electronics, tuned crystals, etc and are preassembled, tested and are usually in miniature form.

When combined with a suitable Antenna the receiver module acts as a complete time code receiver, providing a serial digital data output stream for external decoding.

Once assembled and tested so the module is receiving a signal it can then be connected to your computer or server.

Once connected the time server should be configured using the registry editor. Simply follow these steps:

Locate the following subkey: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersType

In the right pane, right-click Type then click Modify, in edit Value type NTP in the Value data box then click OK.

Locate the following subkey: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeConfigAnnounceFlags.

In the right pane, right-click AnnounceFlags and click Modify. The ‘AnnounceFlags’ registry entry indicates whether the server is a trusted time reference, 5 indicates a trusted source so in the Edit DWORD Value box, under Value Data, type 5, then click OK.

To enable the Network Time Protocol; NTPserver, locate and click: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNtpServer

In the right pane, right-click Enabled, then click Modify. In the Edit DWord Value box, type 1 under Value data, then click OK.

Now go back and click on: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersNtpServer

In the right pane, right-click NtpServer, then Modify, in the Edit DWORD Value under Value Data type In the right pane, right-click NtpServer, then Modify, in the Edit DWORD Value under Value Data type the Domain Name System (DNS), each DNS must be unique and you must append 0×1 to the end of each DNS name otherwise changes will not take effect.

Now click Ok then locate and click the following: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNtpClientSpecialPollInterval

In the right pane, right-click SpecialPollInterval, then click Modify. In the Edit DWORD Value box, under Value Data, type the number of seconds you want for each poll, ie 900 will poll every 15 minutes, then click OK.

To configure the time correction settings, locate: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32Timeconfig

In the right pane, right-click MaxPosPhaseCorrection, then Modify, in the Edit DWORD Value box, under Base, click Decimal, under Value Data, type a time in seconds such as 3600 (an hour) then click OK.

Now go back and click: HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32Timeconfig In the right pane, right-click MaxNegPhaseCorrection, then Modify.

In the Edit DWORD box under base, click Decimal, under value data type the time in seconds you want to poll such as 3600 (polls in one hour)Exit Registry Editor

Now, to restart windows time service, click Start, Run (or alternatively use the command prompt facility) and type:

net stop w32time && net start w32time. And that’s it your time server should be now up and running.

Writen By : Richard N Williams

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about a network time server or other ntp server solutions.

They offer a software for bluetooth cell mobile phones, for messaging, photos and videos between the nearest friends, in a easily and free way.

Certainly, thus that has been demonstrated with phenomena like bluehacking make rage in the United Kingdom, consisting on sending messages, photos and videos through bluetooth with cell mobile phones.

Juan Anacabe, person in charge of BocaEnBoca, said :

It is to be thankful that Bluetooth was created in order to users to wireless connect electronic devices with each other as cell mobile phones, PDAs, computers, MP3 players, hands-free, video games consoles, offering therefore a great comfort for the users.

There is a field in which users demand more from connection facilities offered by Bluetooth, as it is communication with other users, sharing messages, photos and videos whereever, widely spreading them between the nearest friends, in order to participate in their opinions, proposals, recommendations, and interests.

Known as bluehaking, there is a simple way for messaging, with bluetooth cell mobile phones, consisting in creating a new address contact, writing down the message in contact fields & then sending the address contact to other bluetooth cell mobile phones through bluetooth.

This technic is populary used by teens, in order to pick up mates in busy places as underground, but last on offering private messaging, group messaging and simply should be easier as contact address have not been thougth for that solution.

As well, user allways can send their photos and videos through bluetooth, if they are not private ones, one by one, that could benefit from group sharing.

Asked about the features that must prioritize in a service that allows for messaging, photos and videos with cell mobile phones through bluetooth.

He responds that it must be extremely easy for users to present his interests between all his friends, which supposes that should be possible to free send at once to his groups of friends, who he desire, the messages, photos and videos.

In addition, the privacy is due to preserve at all costs, what implies, that these private messages, photos and videos cannot be intercepted by other users, and that these cannot exposed to third users, example of this last one would be, that a photo which you have sent to friends in particular cannot end up resend itself to who you do not wish that sees it.

BocaEnBoca has made specific all it in a software for bluetooth cell mobile phones, that allows users to assign messages, photos and videos that it has in his mobile phone, to its groups of friends, and black lists of blocked users, so that they are sent in chain through bluetooth between friends easily, free and privately.

Anacabe affirms that there are currently millions of users, sending messages, photos and videos between its friends through bluetooth using thier cell mobile phones, being software BocaEnBoca the only proposal that takes care of their specific needs and wishes.

The software, at the present moment, it does not have a cost defined for the moment of its commercial launching, around the 14.50 euro in a unique payment, no mensuals fees, although it is intention of the promoters to posibly be free, offering itself with sponsors endorsement.

There are other articles and a Alpha version, under current development, to download in the page Web of the company at http://http://www.bocaenboca.com

Let’s get the technical bit out of the way first; colour laser printers come in two distinct engine types. The carousel type printer uses for different colour toner cartridges that rotate over a central drum unit, laying down each colour of toner in turn and making a total of four passes over the drum or imaging unit. Epson, Konica Minolta, Lexmark and Samsung all use a variation of this technique. Canon and HP cartridges come in one complete unit per colour that contains both the toner and drum giving each colour its own drum as opposed to sharing a central unit.

So which system is best? There is no correct answer to this question although I personally favour the option used by the Canon, HP duo. With this system there is no uncertainty as to how long the drum will last, it is replaced with every new cartridge. With the carousel system the life of the drum can be dramatically reduced from quoted figures if the colour content of your output rises over the standard 5%. The more colour printing you do the more passes over the central drum unit, the greater the wear on the unit and the more often it will need to be replaced.

If you are replacing an ink printer it is worth bearing in mind that these colour laser printers are somewhat larger, heavier and noisier, so if desktop space is tight check out the dimensions before committing to a purchase.

The smallest, lightest and quietest colour laser printer is the Samsung CLP300, when it was originally introduced this was probably the cheapest colour laser printer on the market and thus an argument could be made for its purchase. Times change very quickly in this market and a sub £90 price is no longer bargain basement territory. If you only intend to print colour text and charts then it will perform well enough but the quality of any colour output beyond this will I fear disappoint.

Moving to the dearest will give us the Lexmark C500N. This printer is almost twice the price of the tiny Samsung and in true Lexmark style is also the most expensive to run, in its favour it is network ready and has the fastest mono speed but this does nothing to compensate for its high costs.

The Epson AcuLaser C1100 has been one of my favourite colour printers since its introduction, it is still one of the fastest printers of its type and print quality is still above average, I feel however that it is now getting a little long in the tooth and the new Konica Minolta Magicolor 2530DL now offers several advantages. With an ethernet 10/100 base TX interface for networking and Pictbridge via a special USB on the front for downloading direct from a digital camera this has moved the goalposts and it tries to replicate ink printer facilities closer than seen before on colour laser printers. The standard 64mb Ram is also twice that on offer from the Epson and should ensure capable handling of even the most complex colour work. Whilst print quality is above average, the printer speed, especially for colour disappoints and is this printer’s major flaw. Be aware also that both these printers are delivered with low capacity cartridges offering only 1,500 colour prints, these will require replacing all too soon. The upside is that high capacity cartridges are readily available and offer better value with a capacity at around 4,500pages.

That just leaves the HP Color Laserjet 1600 and the Canon i-Sensys LBP5000 to be considered. Both of these printers use the same Canon engine so it comes as no surprise that the specifications match with a print speed of 8ppm and a print quality of 600x600dpi. Neither of these printers has an abundance of memory with the HP the most generous at 16mb, the Canon’s 8mb is particularly stingy and may struggle to cope with very complex colour work. The other main difference is in the price, the HP printer can easily be found online at a price under the magical £100 mark whereas the Canon at £50 more is competing with the HP’s big brother, the Color LaserJet 2600. As is the norm the printers are shipped with starter cartridges which give a maximum yield of 1,000 pages and will need to be replaced fairly quickly, fortunately both HP original cartridges and compatible cartridges are readily available from around £120 for a full set of cartridges yielding 2,000 pages.

We have used HP laser printers in our own offices for many years and have always found them to be both reliable and economical, especially if compatible cartridges are used. We have noticed some criticism online of a problem with colour bleed with the HP Color LaserJet 1600, we have not been able to substantiate these claims and only a small number of users seem to experience it, I am beginning to wonder if the quality of the paper may be at fault and not the printer. We have tried using some fairly low quality paper in an attempt to replicate the fault but so far have not experienced any degree of colour bleed.

So, if you are looking for your first Colour Laser Printer, and do not want to spend a fortune, look no further than the HP Color LaserJet 1600 – a fine buy at less than £100.

Written By : Alan Wilson

Alan Wilson has over 10 years experience in the imaging industry and is a director of Cartridge Concept, supplier of discount toner cartridges for all laser toner printers.