DSL, Cable or T1/PRI?
Monday, December 1st, 2008by Mitch Scott
Orlando Florida - We often get asked what is the best solution for connectivity - DSL, Cable or T1/PRI? Each solution has advantages and disadvantages. Let’s start with the basics and look at each solution:
DSL, Cable and a T1/PRI are all Internet connections. They allow you to upload and download data from the Internet. The speed that you are able to upload and download information is referred to as bandwidth. Bandwidth is measured in bits per second. A bit being the information capacity of one binary digit (Data is made up of a stream of 1’s and 0’s called binary digits). Download speeds will effect you receiving information from the Internet (looking at a web page, downloading a file or streaming media). Upload speed will effect you sending information out (such as emailing a large file).
DSL
DSL stands for Digital Subscriber Line. When using a DSL data is transferred over a copper phone line. This data is transmitted at a frequency higher than what is used for a voice conversation. This is why you can use one connection for data and voice. Most DSL lines are asymmetrical (ADSL) which means the rate at which they upload data is different than the rate that they download data. A typical DSL line will allow you to upload at 400Kbps (409,600 bits per second) and download at 1.4Mbps (1,468,006.4 bits per second).
Cons: If your DSL service goes down response time from the ISP (Internet Service Provider) may take several days. If the telephone line is being used for things other than DSL you must use a filter which may make installation more difficult.
Cable
Cable Internet service is delivered over the same coaxial cable that you use for cable TV. Internet access is piggybacked onto the cable television signal in much the same way DSL is piggybacked onto a telephone line. The television signal that is transmitted over the coaxial cable only uses a small portion of the bandwidth (amount of information that can be sent) that is available. Some of that left over bandwidth is simply used to give you Internet access. Cable speeds can theoretically go as high as 30Mbps (31,457,280 bits per second!) but most providers offer speeds between 1Mbps (1,048,576 bits per second) and 6Mbps download and 128Kbps to 768Kpbs upload speed. The drawback to cable is your connection is shared with other businesses or neighbors in the area. If there is a lot of traffic in your area you may notice that your internet connection seems slow.
Cons: Connection speed is shared with other people or customers in your area. Response time when Internet is down may not be as fast as with a T1/PRI.
T1/PRI
A T1 is a digital trunk that carries data, voice or both. In its most basic form a T1 is a tunnel that is capable of uploading or downloading 1.5Mbps worth of data. This can consist of strictly data, up to 24 voice channels (think phone lines) or a combination of both. A T1/PRI can easily support a company with 50 employee’s. A T1/PRI has several advantages over DSL and Cable:
- The T1 bandwidth is dedicated to your company. It is not effected by other people using their Internet connection.
- The T1 has a much higher SLA (Service Level Agreement). If your T1 goes down, the phone company will have it back up and running much faster than if your cable or DSL goes down.






