DS1 and T1

Digital Signal 1 is a signaling protocol used on T-1 carrier lines. The scheme was originally developed by Bell Laboratories. It is a widely used standard for telecommunications in the United states, Canada, and Japan. The European counterpart for the T1 carrier, the E1, also uses DS1 as its signaling protocol. In many technical papers and discussions, DS1 and T1 are often used interchangeably, but the T1 is actually the physical layer, while the DS1 is the logical layer for this networking circuit.

Fractional T1

A T1 circuit is comprised of 24 8-bit DS0 channels, also known as timeslots. Each timeslots can transmit 64kbit/s. When one or more DS0s from a T1 are dedicated to a particular use, it is often referred to as a fractional T1 circuit. Such fractional T1 circuits can be provisioned as either dedicated or burstable. Dedicated circuits mean that the full capacity of only those DS0 channels dedicated are always available to the customer. Burstable configurations mean that the bandwidth of the dedicated DS0s is always available, but the customer may also get additional bandwidth from the rest of the DS0 channels under heavy load, usually for an additional fee.

Voice T1

Voice T1 is a special type of telephone line service specifically designed to allow several users at a time. It is also designed to provide multiple access for computer modems and phones simultaneously. In fact, the Voice T1 offers the use up to 24 lines concurrently.

PRI T1

An ISDN-PRI (Integrated Services Digital Network-Primary Rate Interface). Often this is referred to simply as a PRI. An ISDN PRI T1 might be called a T1 on steroids. The difference is that a PRI uses a D channel (data channel). A PRI uses one of the 24 channels available in a T1 as the D channel. This channel carries the customer call information and control signals rather than an actual call. A PRI can provide the information for Caller ID and screen pops, customer information and history that “pops up” on a compute screen prior to an incoming call being answered.

Data T1

A Data T1 is exactly what the name implies, a T1 configured to transport data signals rather than voice traffic. Often synonymous with the term Internet T1, a data T1 uses the full 1.544 Mbps for internet traffic. Data T1’s have becoming increasingly more popular with the increased demand for VoIP (Voice over Internet Protocol) services. VoIP requires a reliable and stable internet connection to work properly.

Integrated T1

An Integrated T1 combines both voice and data services on the same T1. Integrated T1 service can be configured by allocating a certain number of channels to voice service and leaving the rest of the bandwidth to data or internet service. When configured in this fashion, the bandwidth for the Internet never changes. The voice channels simply lay dormant when now phone calls are being made or received.

Dynamic T1

A dynamic T1 is an integrated T1 that will instantly allocate bandwidth to a phone call on an as needed basis. When a call comes in or when an outside line is accessed, a device referred to as a CSU/DSU pulls the required bandwidth needed for the call and dedicates it to that conversation. As soon as the call is completed the bandwidth is released and again made available for data use.

Bonded T1

A Bonded T1 can give speeds over 1.544 Mbps. Bonded T1’s combine multiple T1’s to make them work as a single circuit. The equipment at each end of the circuit, and its configuration, will determine the speed, routing, type, cost, etc. of the T1. The T1 provider will also make a difference. Each T1 provider will vary in their services offered, provisioning, service guarantees, footprint, etc. T1 prices also vary greatly.

The delivery of a Bonded T1 service can be accomplished using multiple T1 carrier circuits, or can be implemented using a fraction of a T3 carrier instead. This latter type of bonded T1 is usually much less expensive. Common bonded T1 offerings offer 3Mbit/s, 6Mbit/s and 12Mbit/s speeds.

DS3 and T3

DS 3 circuits provide clients with nearly 45 Mbps, 44.736 Mbps to be exact. A DS3 operates as 28 T1s multiplexed together. DS3 lines can be bonded together to provide higher bandwidth. Conversely, fractional DS3 are also available.

DS3 service is used within enterprises requiring very high levels of bandwidth. Medical facilities sharing digital imaging, ISPs requiring high bandwidth backbones, printing companies sharing large files and educational facilities & school districts are prime users of DS3 services.

Fractional T3

Like a fractional T1, a fractional T3 is the dedicated use of a portion of a T3 to a customer's use. Normal fractional T3 offerings involve pairs of the T1s which make up the T3.

Bonded T3

When 44 Mbit/s is just not fast enough, multiple T3 carriers can be bonded together to act as a single circuit.

DSL and Business Internet

DSL (Digital Subscriber Line) technology uses existing telephone lines to carry both voice and data at the same time. This allows you to use one telephone line to access the Internet and talk or fax at the same time on the same phone line. With DSL Service using a router, you can connect multiple computers to a single DSL connection for one flat monthly price. Multiple users can share a DSL connection with separate mailboxes — virtually eliminating the need for multiple dial-up accounts.

ADSL - Asymetric DSL

ADSL (Asymmetric Digital Subscriber Line) is a technology for transmitting digital information at high bandwidths on existing telephone lines to homes and businesses. ADSL simultaneously accommodates both analog (voice) and digital data on the same line. ADSL is asymmetric in that it uses most of the channel to transmit downstream to the user and only a small part to receive information from the user.

Broadband Internet Access

Broadband Internet access, often shortened to just broadband, is high data rate Internet access—typically contrasted with dial-up access over a modem. Dial-up modems are generally only capable of a maximum bitrate of 56 kbit/s (kilobits per second) and require the full use of a telephone line—whereas broadband technologies supply at least double this bandwidth and generally without disrupting telephone use.

Although various minimum bandwidths have been used in definitions of broadband, ranging up from 64 kbit/s up to 1.0 Mbit/s, the 2006 OECD report is typical by defining broadband as having download data transfer rates equal to or faster than 256 Kbit/s, while the United States FCC, as of 2008, defines broadband as anything above 768 kbit/s. The trend is to raise the threshold of the broadband definition as the marketplace rolls out faster services.

Data rates are defined in terms of maximum download because several common consumer broadband technologies such as ADSL are "asymmetric"—supporting much slower maximum upload data rate than download.