DS3 stands for Digital Signal 3, a standardized switched circuit TDM telecom service. As a refresher, DS0 is the basic building block at 64 Kbps. That’s one channel of digitized telephone call. DS1 is a bundle of 24 DS0 channels at 1.5 Mbps. You are probably more familiar with its implementation as a line service called T1. DS3 is the next step up at 45 Mbps. It’s a bundle of 672 DS0 channels as a large telephone trunk or 28 T1 lines multiplexed together for transport. When you order a T3 line, you are getting the line service implementation of DS3.
Even though DS1 and DS3 were originally conceived as telephone company technologies, they are more often used to transport data packets today. That includes private point to point lines and dedicated Internet connections. In these applications, the entire payload is used to transport data packets.
A full DS3 circuit will give you 45 Mbps bandwidth in both the upload and download directions. This is the most common service ordered and is readily available nationwide. You’ll need an interface card for your router to connect to a DS3 termination. There are two interconnect cables, one for transmit (upload) and one for receive (download). They are 75 ohm coax, similar to what you’ll find for Cable TV connections, although the specified cable type is Bellcore 734 or 735 for this application. The connectors are type BNC. You’ll find these on the router interface card. There may be more than one pair if the router can handle multiple DS3 connections.
At this point, you might be imagining coaxial cables stretched from your building back to the telephone central office, like the twisted pairs used for T1 and multi-line telephone service. In practice, the coaxial connection is only used for short distances. The DS3 bandwidth itself is most often delivered over a SONET fiber optic cable, where it is demultiplexed and dropped off at your premises.
DS3 bandwidth may be higher than you require. There’s a big gap between T1 line bandwidth at 1.5 Mbps and DS3 at 45 Mbps. Companies often begin scaling up their bandwidth by bonding multiple T1 lines to double or triple the individual line bandwidth. This works up to about 10 or 12 Mbps in most cases. Let’s say you only need 20 or 30 Mbps right now. What do you do?
One option is to order fractional DS3 service. A full DS3 interface is installed, but the line bandwidth is limited to the fractional amount you order. That could be 15, 20 or 30 Mbps. You can possibly save money this way, but not necessarily. The reason is that full DS3 is more of a standard service that is readily available. The fractional services are a special order that may or may not be available in a particular location, depending on the service provider. In the end, it might make the most economic sense to get a full DS3 connection.
There are other technical options in this bandwidth range that compete with fractional and even full DS3. The most popular is Ethernet over Copper. This is a highly scalable service that competes with T1 at the 1.5, 2, and 3 Mbps levels. You can also get 10, 15, 20, 25, 30, 50, and sometimes even 100 Mbps Ethernet over Copper. This lets you match your budget more closely to the bandwidth you require. Ethernet over Copper (EoC) is often less expensive than either T1 or DS3 for similar bandwidths, although not as readily available as yet.
Downtown in major business districts you may also find fixed wireless bandwidth services. These often deliver DS3 bandwidths, but perhaps in an Ethernet protocol. Most of the time that’s what you want anyway, since you’ll be connecting to a LAN running Ethernet.
A final option isn’t DS3, but might give you a similar benefit for a lot less money. That’s business class Cable broadband. It is shared, not dedicated, and the bandwidth varies with the amount of user activity. Still, you can get up to 50 or 100 Mbps download with 5 or 10 Mbps upload service for about the price of a T1 line. You’ll need to have the cable passing by your business location for this service to be available. Otherwise the construction costs are prohibitive.
Are you in need of higher bandwidth to support your growing business, additional computerization or a move to cloud services? If so, get pricing and availability for DS3 and fractional DS3 services, plus related bandwidth services that may also meet your needs.