We receive information in a number of ways. For example, we can
listen to the radio, watch TV, talk on the telephone or use our computers to reach the Internet. In general we are receiving information in two distinct ways. In one case we are listening to the same information that is broadcast to everyone, and in the other case we are receiving a private message. No matter how we receive the information it is important that the message is loud and clear. Let’s take a look at some of the factors that affect the quality of what we receive.Broadcast versus Addressed Information
First let’s understand the difference between receiving the information that’s broadcast versus getting information that’s addressed to us. The reason I’m reviewing the two types of communication is because it is helpful to know this when you are talking to your network provider. Some of these providers actually don’t understand this concept, so you have to help them along, especially when you are trying to explain a problem you’re having with their service.
When information is broadcast electronically, it is like a water pipe filled with fish. The pipe goes from one house to
another and at each house there is a window in the pipe through which you can see the fish swimming. Since people are all looking at the same fish (information), you just need to have enough water pressure for the water to reach all the houses in the neighborhood. No one is taking any of the fish away. Cable television broadcasts TV signals so that everyone sees the same information (the fish) at the same time. Cable companies monitor the quality of the signal reaching each location to assure you get a good quality TV signal.Sending information that’s addressed to specific computers is like delivering the fish to each person’s house. When you connect your computer to the Internet you get some data (fish) that’s addressed just to you. Each house takes some of the fish away so you need lots of fish. IP addresses are used on the network to address each of the computers and to assure that the information gets to the right place. Telephones are another example of addressed information. You call a specific house by using a specific phone number. Internet providers that focus on good data service should not only be interested in the quality of the signal, but also the bandwidth (amount of fish) that each user receives.
Data rate (or do we have enough fish).
The data or bit rate is related to the bandwidth available and it is a measure of the amount of information (number of fish) that can be sent over any transmission media. The data is sent over a transmission media that can be a cable wire, an optical fibre wire, or wirelessly using a radio. No matter what the transmission media, we are always concerned about the data rate.If many people are trying to get the fish at the same time, you have a fish delay because you don’t have enough fish to go around. For example if the Internet provider tells you that you have a 10 Mbits/sec connection, you may not receive this data rate all the time. The problem is that the network is shared by many people so sometimes the bandwidth that you receive is reduced and you end up waiting a long time for a picture to load on your web browser. It’s far worse when you are talking to someone on the telephone, and there are missing sounds or interruptions to the voice.
When you have these problems it’s time to talk to your provider about the bandwidth they are actually providing.
How High a Data Rate Do We Really Need?
The data rate you need depends on what information you want to send. When you send real-time audio or video data it’s very important to receive a continuous flow of information. For example if you want to transfer video on the Internet, the data rate required will be determined by the resolution of the picture, the frame rate (or how many pictures you want to send per second), and the compression scheme you use. If you send video with a resolution of 640 x 480, it uses about 300 Kbits/picture when using MJPEG compression. If I want to send 10 pictures or frames per second, then I will need a data rate or bandwidth of 10 frames/second x 300 Kbits = 3000 K bits/second. This is the same as 3 Mbits/sec. So if we want to see the video at 10 frames/sec, we will require a bandwidth of at least 3 Mbits/sec.Many DSL, cable companies and Verizon FIOS have one data rate for incoming (download) data rate and another for the outgoing (upload) data rate. Usually you would like a higher download rate, but sometimes, especially if you are viewing a camera, you would like a higher upload rate.
Now that you understand the concept of data rates, you will be better able to make the right choices for your Internet connection. These same concepts also apply to your local area network and even your wireless network.
If you need more help determining bandwidth (how many fish) you need, just give us a call at 914-944-3425 or use the contact form to send us a message.
The NVR or IP software is a major advance over the VCR and DVR. The introduction of network attached IP cameras around 1996 required a new type of recording system to be developed. Instead of using coax cable to distribute the video, the video is digitized and compressed in the camera and attached directly to the Ethernet network. The digitized video is now distributed over the network just like any other computer data. A number of software and hardware products were developed to support these new IP cameras. The software runs on standard computers connected to the same Ethernet network as the IP cameras. The software transformed the standard computer into a Network Video Recorder. Now many hundreds of IP cameras can be supported by this IP NVR software. Prices range from $500 to well over $25,000 (for hundreds of cameras).
The software uses your own computer and it will allow you to view, store and retrieve video and control the cameras. There are a number of common capabilities and each package also has some unique features and functions. For example, all versions allow you to view the video using a web browser from anywhere on the Internet, store video only when motion is detected, and notify you of motion alarm by email or by an alarm sound on the PC. NetDVR and NetDVMS are more robust server/client type software and add among other things the ability to patrol through preset PTZ positions and to transfer the video to alternative storage on the network.