For a good internet connection, you or your company should look into a T3 cable.  With a DS3 connection, you can keep in touch with friends, family and business associates with ease and for a low T3 cost.  DS3 service running over a T3 line or multiplexed on a OC3 or higher optical carrier works well for transporting digital video signals using reasonable amounts of compression.

A couple of HDTV signals will fit into the 45 Mbps bandwidth of DS3. Less compression can be used to transmit a single higher quality video stream for video production work, digital cinema or medical imaging use. If truly raw video is needed, OC3 at 155 Mbps, OC12 at 622 Mbps or OC48 at 2.488 Gbps are available.

Otherwise, DS3 offers an excellent price point, wide availability, and enough bandwidth for most video applications.

Raw digital conversions of analog signals can use up a lot of bandwidth fast. The standard telephone Pulse Code Modulation codec called G.711 spits out a stream of 64 Kbps for each telephone conversation. Phone conversations are hardly what you'd call high fidelity. A real Hi-Fi stereo signal needs about 1.5 Mbps, which fits nicely on a T1 line. Video needs even more.

A HDTV video signal needs 1.5 Gbps. That's 1,000 times what you need for audio. Even the standard NTSC video consumes about 143 Mbps. If video signals stayed in that format, you could forget transmitting them outside the studio or even recording them on DVDs.

In addition, one nice thing about digital video signals is that digital line services can be used to transport them between offices or cross-country. Digital video can be standard or HDTV broadcast programs, two-way video conferencing, medical imaging, security cameras and even digital cinema.

Also, the process of transmitting video digitally is quite a bit like what is done for digital telephony and digital broadcast audio. It all starts with a device called a CODEC or Coder. This coder is the component that converts from analog to digital and back again. It also performs whatever compression is needed to fit the original signal through a particular size channel.

High speed digital private lines, such as T1 and T3 carriers, got their start transporting telephone conversations. Over the last few years, businesses have pressed this technology into service to expand their local area networks and to tie their PBX telephone systems together. One more recent trend has been using digital networks to converge or combine data and voip telephone services.

The video standard is NTSC, has an analog bandwidth of 4.2 MHz and, with audio, is transmitted in a 6 MHz TV channel. Some clever engineering allowed color information to be squeezed into the same channel size. Currently, the majorities of TV sets are still analog and still use the NTSC standard.

However, TV broadcasting is migrating to a new digital high definition standard, HDTV, and satellite and many cable TV signals are delivered digitally. They can then be used as digital inputs to high resolution monitors or converted to analog for monitors and TV sets that need that format. For video, the standard compression format is called and the most popular format is MPEG-2.

This is used for HDTV broadcasting and satellite TV. MPEG-2 does its magic by monitoring what is changing in the scene and only transmitting that.