D4 Technology

Overview | Cross Reference | FAQ

D4 Technology
Pulsecom's D4 Solution

What is D4?
The term D4 is derived from Digital 4th generation, an evolution of products beginning with the industry's first digital transmission system called D1, developed by Bell Laboratories. D4 systems accept DS1 (1.544 Mbps T1) signals and convert them to 24 separate 64 Kbps (DS0) voice or data circuits and/or a combination of higher bandwidth links (or vice versa).

What are the advantages of D4?
D4 is an open-architecture system that supports plug-in channel cards from over a dozen vendors, ensuring users of optimum availability, pricing, flexibility, and support.

Are D4 applications restricted to only telephone company central offices?
No. D4 equipment may be wall-mounted, integrated at business locations, and even deployed in outdoor cabinets. No other technology offers this range of capability.

How does D4 work?
D4 works much like a CD player. Information that is encoded in digital form is sent over a telephone company or private network at high speed, but in several separate channels, similar to the digitally encoded tracks on a CD. The D4 system accesses these bits and reproduces voice or data in a user-friendly format (RS-232, tip/ring pairs, etc.) just as a Hi Fi system and CD player work together to produce music.

Doesn't D4 convert all signals to analog "PAM" signals, resulting in degraded digital performance?
No. D4 has a sophisticated parallel bus architecture that provides pure digital transmission over a separate digital bus as well as high quality voice circuits over a parallel and separate voice bus.

What does the future hold for D4?
D4 is continually being improved and refined to enhance the services and quality of the telecommunication network without the risks associated with other communication schemes. With tomorrow's need for flexibility, proven performance, and open architectures, D4 offers far more long-term security and support than any other platform. Today, D4 offers more data capabilities, more voice capabilities, and more deployment capabilities than any other system in the world. Advanced features for tomorrow, such as IDSL, SDSL, and HDSL, are added to continuously expand network performance.

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Pulsecom's D4 Solutions:

What products are included in Pulsecom's D4 Solution?
Pulsecom manufactures and supplies the broadest line of D4 products in the industry, including:

D4 Chassis

  • BusinessBank® T1 Access Multiplexers
  • 16:i high density ISDN and Frame Relay Intelligent Access Multiplexers
  • BusinessCarrierTM outside plant data/voice service nodes
  • Comprehensive data services, including direct RS-232/V.35, ISDN, All Rate DDS, Datapath, High Rate RS-422/522, Fractional T1, Analog Telemetry, and Message Waiting support
  • Comprehensive voice services, from high fidelity to E&M, POTS, Coin, Meridian® (P-Phone), DX, Line Side Answer Supervision, PBX, etc.
  • TR-303 and DCS-compatible intelligent common equipment, integral power/ringing, SF/ESF/B8ZS, Drop and Continue, dial-up maintenance, etc.

What are the configurations of Pulsecom's D4 bays?
Each D4 assembly consists of a seismic-rated 23" rack and one or more 48-channel banks. Pulsecom 23" channel banks are standard industry configurations and fit "hand-in-glove" with existing bays and office equipment.

Can I use HDSL with Pulsecom's D4 systems?
Yes. There are several ways to use HDSL with Pulsecom's D4 system:

  • A number of vendors offer fractional T1 HDSL channel units that support rates of up to 768 Kbps, using a single pair HDSL loop.
  • Pulsecom's BusinessBank and BusinessCarrier feature direct integration of Type 400 card HDSL T1 rate equipment to enable same-day system turn-up.

Can any of Pulsecom's D4 products support multipoint data networks?
Yes. The Pulsecom Quad Multipoint Junction Unit (QMJU) with Secondary Channel converts a D4 channel bank into a multipoint digital data facility capable of using Dataphone Digital Service (DDS) or any other basic digital service. The QMJU provides the capability of creating local multipoint hubs or nodes at any central office.

Is it possible to support MFT applications with Pulsecom's D4 systems?
Yes. Pulsecom offers a Metallic Facility Digital Terminal (MFDT) configuration for standard, reliable, and readily available D4 channel banks. The MFDT accommodates both analog and digital locally served circuits with off-the-shelf circuit packs. Installed with the D4 channel bank's A-digroup DS1 line connected to the B-digroup DS1 line, up to 24 analog-line or digital-line DS0 circuits can be provisioned in a 19" high D4 chassis.

What is the difference between Pulsecom's BusinessBank and the BusinessCarrier?
The BusinessBank is built for indoor use, and the BusinessCarrier is designed for outdoor use.

What Special Services do Pulsecom's BusinessBank and BusinessCarrier support?
Pulsecom's BusinessBank and BusinessCarrier systems are able to accept all standard D4 channel units, including ISDN, Switched 56 Kbps data, OCU Dataport, Program Channel, Foreign Exchange, 4-Wire and 2-Wire Voice Grade Private Lines, DX, DID/DOD, E&M, and many others. The BusinessBank and BusinessCarrier are the most cost-effective Special Service delivery platforms available. Compared with traditional DLC Special Service provisioning, these products can provide savings in excess of 50%.

Do the BusinessCarrier systems provide Hi Cap drops?
Yes. Since Special Service customers often also subscribe to Hi Cap circuits, the BusinessCarrier provides up to three Hi Cap drops from their fully integrated fiber interface. These Hi Cap drops may be conventional T1 span lines, HDSL circuits, or even T1 rate fiber drops.

Is Pulsecom's BusinessCarrier "climate hardened"?
Yes. The BusinessCarrier is a climate-hardened, 24-channel D4 transmission system intended for outside plant installation. It is housed in a fully TR-000497 compliant sealed cabinet, equipped with full battery, thermal, and charging management.

Are the BusinessBank and BusinessCarrier systems compatible with ISDN?
Yes. All Pulsecom D4 systems are plug-and-play ISDN ready. Not only can you mix ISDN with other data and voice services, you can mix Pulsecom ISDN circuit boards with ISDN circuit boards from a number of other vendors.

What are the key advantages of Pulsecom's BusinessBank and BusinessCarrier systems?

  • The BusinessBank and BusinessCarrier offer more voice and data capabilities than any other system.
  • The T1 BusinessBank and BusinessCarrier can move data or voice economically from one location to another over standard T1 or "Hi-Cap" telephone company leased lines.
  • The BusinessBank and BusinessCarrier can be connected to local telephones located over 10 miles away over standard telephone wires.
  • The BusinessBank and BusinessCarrier can handle all types of telephone signaling equipment.
  • The BusinessBank and BusinessCarrier can provide special circuits (e.g., Hot Line and Automatic Ringdown telephones).

The BusinessBank and BusinessCarrier systems offer more voice and data capabilities than any other system. Users can mix PBX circuits; automatic ringdown; key or standard telephones; E&M, DX, FXO/FXS, DPO/DPT signaling; ISDN and analog; digital multidrop, video, and switched data in the way that best meets their business needs.

What are typical applications of Pulsecom's BusinessBank and BusinessCarrier systems?
Typical applications include the following:

  • Remote bank teller machines
  • State lottery terminals
  • Smart cash registers at department stores or grocery stores
  • High-speed data transfers (checking account reconciliation or airline bookings) and
    video conferencing

More specialized applications may include remote equipment control or burglar alarm surveillance.

Are Pulsecom's BusinessBank and BusinessCarrier systems compatible with SONET equipment?
Yes. These systems can serve as SONET-fed terminals and special service gateways.

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