Dialogic DIALOG/4

Half-Size, Four-Port Voice Processing Board

Features and Benefits

• Four independent voice processing ports in a single, half-size PC ISA slot supporting low- to medium-density voice systems
• Downloadable signal and call processing firmware facilitates feature enhancement and provides field-proven performance based on over 3 million installed ports
• C language application program interfaces (APIs) for MS-DOS*, Windows 95*, Windows NT*, OS/2(r), and UNIX(r) shorten your development cycle so you can get your applications to market faster
• Application generators available from third-party providers
• Configure multiple DIALOG/4 boards in a single PC for easy and cost effective system expansion, and to build scalable systems from 4 to 64 ports
• Voice coding at dynamically selectable data rates, 24 Kb/s to 64 Kb/s, selectable on a channel-by-channel basis for optimal tradeoff in disk storage and voice quality
• Enhanced telephone circuitry and automatic gain control maintains recording quality over a wide dynamic range
• Perfect Digit DTMF (touchtone) provides reliable detection during voice playback - allows callers to "type-ahead" through menus
• Patented outbound call progress analyzes outgoing call status quickly and accurately
• Supports PBX Expert and PBX Expert/32, utilities that simplify switch integration
• Lifetime warranty

Applications

• Voice mail/voice messaging
• Interactive voice response
• Audiotex
• Inbound and outbound telemarketing
• Operator services
• Dictation
• Auto dialers
• Telecomputing servers
• Notification systems
• On-line data entry/query

The DIALOG/4 board, with its half-size footprint, is an ideal solution for computer telephony installations that cannot take full-size voice boards. It provides four telephone line interface circuits that are approved for direct connection to analog loop start lines. A dual-processor architecture, consisting of a DSP (Digital Signal Processor) and a general-purpose microprocessor, handles all telephony signaling and performs DTMF (touch tone) and audio/voice signal processing tasks. Multiple DIALOG/4 boards can be installed in a single PC chassis enabling system expansion up to 64 ports.

Voice products offer a rich set of advanced features, including state-of-the-art DSP technology and signal processing algorithms, for building the core of any computer telephony system. Downloaded firmware algorithms executed by the on-board DSP provide voice coding at 24 and 32 Kb/s ADPCM, and 48 and 64 Kb/s PCM. Sampling rates and coding methods are selectable on a channel-by-channel basis. Applications may dynamically switch sampling rate and coding method to optimize data storage or voice quality as the need arises. Downloaded firmware algorithms also provide reliable DTMF detection, DTMF cut-through, and talk off/play off suppression over a wide variety of telephone line conditions. Enhanced telephone circuit design and automatic gain control maintains recorded voice quality even at extremely low signal levels.

The DIALOG/4 voice board:

• Connects directly to the telephone line
• Automatically answers calls
• Detects touch tones
• Plays voice messages to a caller
• Digitizes, compresses, and records voice signals
• Places outbound calls and automatically reports the results all in real time on four independent channels.

Configurations

The DIALOG/4 board shares a common hardware and firmware architecture with other voice boards for maximum flexibility and scalability. You can easily add new features and/or expand the size of the system while protecting your original investment in hardware and application code. Applications can be ported to lower or higher line-density platforms with minimal modifications.

The DIALOG/4 board installs in IBM PC XT/AT* (ISA bus) and compatible computers (Intel386™, Intel486™, or Pentium® processor-based PC platforms). The DIALOG/4 board provides everything required for building integrated voice solutions scalable from four ports to 64 ports.

Software Support

The DIALOG/4 is supported by System Software and SDK for MS-DOS*, Windows NT*, Windows 95*, OS/2*, and UNIX*. These packages contain a set of tools for developing complex multichannel applications.

Functional Description

The DIALOG/4 board uses a dual-processor architecture that combines the signal processing capabilities of a DSP with the decision-making and data movement functionality of a general-purpose 80C188 control microprocessor. This dual processor approach offloads many low-level decision-making tasks from the host computer enabling development of more powerful applications. This architecture handles real-time events, manages data flow to the host PC for faster system response time, reduces host PC processing demands, processes DTMF and telephony signaling, and frees the DSP to perform signal processing on the incoming call.

Each of four loop start telephone line interfaces on the DIALOG/4 board receives analog voice and telephony signaling information from the telephone network (see block diagram). Each line interface uses reliable, solid-state hook switches (no mechanical contacts) and FCC part 68 class B ring detection circuitry. This FCC-approved ring detector is less susceptible to spurious rings created by random voltage fluctuations on the network. Each interface incorporates circuitry that protects against high-voltage spikes and adverse network conditions allowing applications to go off-hook any time during ring cadence without damaging the board.

Inbound telephony signaling (ring and loop current detection) are conditioned by the line interface and routed via a control bus to the control processor. The control processor responds to these signals, informs the application of telephony signaling status, and instructs the line interface to transmit outbound signaling (on-hook/off-hook) to the telephone network.

The audio voice signal from the network is sent through a bandpass filter, conditioned by the line interface, and then applied to a CODEC (COder/DECoder) circuit. The CODEC filters, samples, and digitizes the inbound analog audio signal and passes the digitized signal to a Motorola DSP.

Based on Spring Ware firmware loaded in DSP RAM, the DSP performs the following signal analysis and operations on this incoming data:

• Automatic gain control to compensate for variations in the level of the incoming audio signal
• Applies an ADPCM (Adaptive Differential Pulse Code Modulation) or PCM (Pulse Code Modulation) algorithm to compress the digitized voice and save disk storage space
• Detects the presence of tones - DTMF, MF, or an application defined single- or dual-frequency tone
• Silence detection to determine whether the line is quiet and the caller is not responding

For outbound data, the DSP performs the following operations:

• Expands stored, compressed audio data for playback
• Adjusts the volume and rate of speed of playback upon application or user request
• Generates tones - DTMF, MF, or any application-defined general-purpose tone

The dual-processor combination also performs outbound dialing and call progress monitoring:

• Transmits an off-hook signal to the telephone network
• Dials out (makes an outbound call)
• Monitors and reports results: line busy or congested; operator intercept; ring, no answer; or if the call is answered, whether answered by a person, an answering machine, a facsimile machine, or a modem.

When recording speech, the DSP can use different digitizing rates from 24 to 64 Kb/s as selected by the application for the best speech quality and most efficient storage. The digitizing rate can be selected on a channel-by-channel basis and can be changed each time a record or play function is initiated. Outbound processing is the reverse of inbound processing. The DSP processed speech is transmitted by the control microprocessor to the host PC for disk storage. When replaying a stored file, the microprocessor receives the voice information from the host PC and passes it to the DSP, which converts the file into digitized voice. The DSP sends digitized voice to the CODEC to be converted into analog voice and then to the line interface for transmission to the telephone network.

The on-board microprocessor controls all operations of the DIALOG/4 board via a local bus and interprets and executes commands from the host PC. This microprocessor handles real-time events, manages data flow to the host PC to provide faster system response time, reduces PC host-processing demands, processes DTMF and telephony signals before passing them to the application, and frees the DSP to perform signal processing. Communications between this microprocessor and the host PC is via the shared RAM that acts as an input/output buffer increasing the efficiency of disk file transfers. This RAM interfaces to the host PC via the XT/AT bus. All operations are interrupt-driven to meet the demands of real-time systems. All DIALOG/4 boards installed in the PC share the same interrupt line. When the system is initialized, firmware to control all board operations is downloaded from the host PC to the on-board code/data RAM and DSP RAM. This downloadable firmware gives the board all of its intelligence and enables easy feature enhancement and upgrades.

Technical Specifications

Spring Ware Firmware Technical Specifications

All specifications are subject to change without notice.
** Average speech mandates +16 dB peaks above average and preserves -13 dB valleys below average.
§ Analog levels: 0 dBm0 corresponds to a level of +3 dBm at tip-ring analog point. Values vary depending on country requirements; contact your Intel Sales Engineer.

Hardware System Requirements

Intel386™, Intel486®, or Pentium®, IBM PC AT* (ISA) bus or compatible computer. Operating system hardware requirements vary according to the number of channels being used.

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