Comdial Dxp Plus Instructions Manual

Services Board
Status
Red
Yellow
Sync
Signal
Blue
Bipolar
CRC
Slip
Unlock
B8ZS/COFA
Remote Loopback
Local Loopback
Payload Loopback Primary
Secondary
Unlocked
Status
Manual
DXOPT-SYN
Card
Diagnostic Switches
and LEDsDXPT1 Board
PLUS007d.cdr
Viewing The Alarms And Indicators
Installing And Programming The DXPRI Card IMI89–255
Viewing The Alarms And Indicators – 35 

Defining The T1/PRI Terms
Bipolar
A bipolar signal is composed of alternating pulses that both represent a digital logic 1. The positive pulse is a (+)
and the negative pulse is a (-). Zero volts represents a space, or digital logic 0.
Bipolar Violation (or error)
A bipolar error is a digital logic 1 (or mark) that has the same polarity as its predecessor.
NOTE: Every time the system regenerates the signal stream, it corrects any bipolar errors; therefore, it prevents
end-to-end error checking from using...

DS-0 (Digital Signal-Level Zero)
Digital Signal-Level Zero is a single 64Kbit channel inside a T1/PRI span.
Extended Super-frame Mode (ESF)
Extended Super-frame Mode consists of 24 frames. The frame bit uses only 6 frames leaving 18 bits for other
purposes. These spare 18 bits provide 6 bits for CRC information and 12 bits for a facility data link. The facility
data link is for maintenance information (as defined by the ANSI T1.403 specification). Like the super-frame
mode, the 64–Kbit user channels have...

LIU Line Interface Unit
The line interface unit is the interface between the copper wires and the T1/PRI board’s framing circuitry. The
LIU is responsible for separating the 1.544MHZ receive clock from the incoming stream and converting bipolar
Alternate Mark Inversion (AMI) to 5–volt digital logic. The LIU also supports the automatic line build-out that
regulates the transmit level according to the receive strength (LIU-2 switch).
Primary Clock Reference
The straps on the DXSRV–PLS board designate the...

Knowing The T1/PRI Specifications
Capacity10 T1/PRI boards
ModesSuper-frame, extended super-frame
FramingD4
Channels Allocated24
Industry StandardsANSI T1.403-1989
AT&T PUB 62411
CCITT 0.921
CCITT 0.931
Maximum Output2.4V to 3.6V base to peak, short circuit
protection to 120 mA, rms
Line Rate1.544 Mbps
Line Code
Type Bipolar AMI
Zero Suppression B8ZS
Receive Sensitivity-26 dB or -36 dB selectable
Impedance100 Ohms
DXP Loss Insertion
Transmit -6 dB (selectable to 0 and -3 dB per channel)
Receive 0 dB...

Up-Grading Your DXPT1 Board For ISDN–PRI Support
Up-grading existing revision B or later DXPT1 boards for ISDN–PRI service consists of adding a DXPRI card to
the T1 board, and changing the board’s chip firmware. When you do this, the T1 board/DXPRI card combination
with the new firmware becomes a DXPT1–PRI board.
If you add the ISDN–PRI firmware to an existing T1 board but do not install the DXPRI card, you create a NFAS
(Network Facility Associated Signalling) DXPT1–NFAS board. The NFAS boards are...

Replacing The Firmware
1. With the DXPT1 board still at your static-safe work area and with your static discharge wrist strap on your
bare wrist and properly grounded, replace the chip-set firmware with the ISDN–PRI firmware.
2. Locate the current chip firmware (U5 at the upper rear of the board—see the illustration), and note its
orientation in its socket.
3. Use a chip extraction tool to lift the chip free from its socket.
4. Remove the replacement chip from its static protection bag and orient it to...

DP. I I I I . .
and
FX SeriesDigital Communications Systems
Understanding The
Visual Man-Machine Interface
COMDlA” 

Table of ContentsIntroducing VMMI........................
1Using the Programming Screens....................
1
Using On-Line Help........................2
Obtaining a Printout Record......................2
Using the Computer Mouse.....................3
Determining Your Equipment Needs..................
3
Connecting a PC to the
Digital Communications System..................
4Connecting a PC to the DXP Plus...................
4Connecting a PC to the DXP....................
5
Connecting Cabling For FX...

GCA40-182Understanding the VMMlIntroducing 
VMMI
Using The Programming ScreensVMMI is a Microsoft* Windows based programming method that is menu-driven and allows you to enter
choices in dialog boxes. The VMMI programming index is expandable much like the file manager on a
computer’s operating system software. As you use your computer mouse to move the screen cursor to the
desired location, and double-click the mouse button on a main menu element, it expands to show sub-menus
that, in turn, open at a...