T1 Fiber Mux, Multimode, 850-nm
Installation and User Guide (Dec-08)
Black Box Explains...ISDN Basics.
Product Data Sheets (pdf)...Network Termination Unit-1 (NTU-1)
ISDN stands for Integrated Services Digital Network. It’s a high-speed digital data service provided by most phone companies. With ISDN you can transmit large amounts of data, voice, and video... more/see it nowsignals up to 128 kbps over a single phone line.
The most common (and least expensive) ISDN service is Basic Rate Interface, or BRI. It’s usually used to combine voice and data circuits over one line between small-scale ISDN sites. BRI consists of two 64-kbps B channels plus a 16-kbps D channel to support system “overhead” functions, such as signaling the telecomm switching system to initiate a call.
What makes ISDN unique is that each B channel is a separate communication circuit. That means just one ISDN line can support simultaneous two-way communication for two devices, such as a computer and a telephone or a computer and a video camera for teleconferencing.
If you need to send more data than one 64-kbps B channel can handle, ISDN also supports BONDing for inverse multiplexing. This links the two B channels into a single logical circuit that can support data rates up to 128 kbps.
ISDN lines are terminated at your location with a special RJ-45 jack. There are two main interfaces. The U interface consists of two wires (one twisted pair) and is common in North America. The S/T interface consists of four unshielded wires (two twisted pairs) and is more common outside North America. Unless you already own U-compatible ISDN phones or PCs, you’ll need a terminal adapter to make the connection.
ISDN is the perfect choice when faster data rates, lower prices, and guaranteed data integrity are required. Consider it for high-volume datacomm applications such as Internet access and on-line service, telecommuting, remote-office routing, and disaster recovery. Also consider ISDN for a high-speed backup line—because you never know when you’ll need one. collapse
Black Box Explains...DDS vs. T1.
Product Data Sheets (pdf)...ISDN Terminal Adapter 128K
Product Data Sheets (pdf)...Compact T1 Channel Bank
DDS (Digital Data Service) is an AT&T® service that transmits data digitally over dedicated leased lines. DDS lines use four wires, and support speeds up to 56 kbps; however, DDS... more/see it nowis actually a 64-kbps circuit with 8 kbps being used for signaling. You can also get 64-kbps (ClearChannel™) service. Since the transmission is digital, no modems are needed. Dedicated digital lines are ideal for point-to-point links in wide-area networks.
T1 is a dedicated transmission line operating at 1.544 Mbps. It’s comprised of 24 DSOs, each supporting speeds of 64 kbps. The user sends data at N x 56 or N x 64 over T1 circuits. T1 operates over twisted-pair cable and is suitable for voice, data, and image transmissions on long-distance networks. collapse
Black Box Explains...T1 channel banks.
Product Data Sheets (pdf)...Asynchronous Local RS-232 Muxes
T1 is a digital transmission method for multiplexing multiple voice and data channels over two pairs of wires.
By using a technique called Time-Division Multiplexing (TDM), T1 interleaves both voice and/or... more/see it nowLAN data across DS0 subchannels. The primary benefit of T1 is bandwidth—1.544 Mbps—available in 24 easily allocated 64-kbps DS0 subchannels.
T1 sends data in frames made up of 24 eight-bit words (one word for each subchannel) and one framing bit for a total of 193 bits per frame. A T1 channel transmits 8000 frames per second.
The framing bits on successive frames follow a pattern for a superframe format. T1 channel banks check this pattern to make sure synchronization is maintained.
T1 is the most flexible end-to-end digital service option available today. Its the preferred service for internetworking voice, data, fax, and video signals across an enterprise network. And Black Box is your supplier of T1 hardware with a broad range of solutions for consolidating your global high-speed network management. collapse