Comdial Dxp Plus Instructions Manual

1.1 Introducing The DXPT1
The DXPT1 is a digital interface board supporting up to 24 simultaneous calls on two pairs of wire. The
advantages of T1 over single-channel systems are largely:
·Cost savings (much lower price per channel)
·Greater reliability
·Uses less copper wires
·Improved voice reproduction
·More features available
T1 is over 20 years old but the services have been upgraded during this time (for example, extended
superframe).
T1 uses time division multiplexing techniques which multiplexes...

1.3 Considering Pre-Installation Details
CAUTION
For operation with the DXP Plus, the T1 board must be Revision B or higher. If the T1 board that you
are installing is a lower revision, contact Comdial Technical Services (1–800–366–8224) for advice
before you proceed with the installation..
If you are the installer, you must consider the following things to ensure a proper installation.
A. Determine the T1 trunk configuration and communicate this to the central office and/or the network
for coordination...

2 Troubleshooting The Physical Layer
SW1, SW2, and the LIU switches must be set up according to the customer’s requirements. SeeInstalling
The DXPT1 Digital Carrier Transmission Option,IMI89–193 for directions.
2.1 Selecting Functions With DIP Switches SW1-1 Through SW1-8
NOTE: SW1 switch contents will be updated only during a reset operation.
The mode, superframe or extended superframe, is critical. If set wrong, the board will not find frame sync
causing the red Sync LED to light.
Yellow alarm mode...

2.3 Selecting Functions With DIP Switches LIU-1 Through LIU-4
There are four LIU switches. The first switch will change the receive sensitivity from -26 dB to -36 dB.
Changing to -36 dB for extra long loops (1 mile) is not recommended unless the DXPT1 will not maintain
frame sync. In the -36 dB setting, noise could be a problem because of increased sensitivity.
The LIU-2 switch sets the transmit signal level. The transmit signal level has nothing to do with the audio
voice levels. The default is manual...

3 Troubleshooting The Protocol Layer
Four protocols are supported:
·E & M
·DID
·Ground Start
·Loop Start
Ground and loop start are subscriber-end only (DXP Plus end) not office-end (network end).
Before starting protocol layer troubleshooting, make sure you have completed all physical layer
troubleshooting to ensure that no alarms are occurring and that the DXPT1 board has no red LEDs lit
except for the large status LED.
Troubleshooting the protocol layer consists of checking the A and B transmit and...

3.2 Defining The Signalling Bits For The Direct Inward Dial (DID) Protocol
FUNCTION TRANSMIT RECEIVE EIA/TIA 464-A
STANDARD
ABAB
INCOMING CALL
Idle
CO goes off-hook
DXP sends wink
DXP after wink
Far end DP
Far end wait FR ANS
DXP answers call0
0
1
0
0
0
10
0
1
0
0
0
10
0
1
1
DP
1
1X
X
X
X
X
X
XMake=1, Break=0
3.3 Defining The Signalling Bits For The Ground Start Protocol
FUNCTION TRANSMIT RECEIVE EIA/TIA 464-A
STANDARD
ABAB
OUTGOING CALL
Idle
PBX grounds ring
PBX grounds tip
PBX removes ring ground
PBX...

3.4 Defining The Signalling Bits For The Loop Start Protocol
FUNCTION TRANSMIT RECEIVE EIA/TIA 464-A
STANDARD
ABAB
OUTGOING CALL
Idle
PBX loop closed
PBX pulsing
Dialing CMPL
INCOMING CALL
Idle
CO sends ring
Interval between ring
PBX presents call
PBX answers call
Normal talking STAT
DISCONNECT PBX
PBX opens loop
Idle
CO ABANDONS INCOM...
CO applies ring
Interval between ring
CO abandons
PBX stop presenting0
1
DP
1
0
0
0
0
1
1
0
0
0
0
0
01
1
1
1
1
1
1
1
1
1
1
1
1
1
1
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
01
1...

4 Using The Diagnostic Function
The diagnostic function on the DXPT1 board provides a method for obtaining information about the T1
operation. You can do this either on-site or from a remote location by sending and receiving coded
messages. Remote operation is described in section 4.8.
4.1 Understanding The Diagnostic Switches And Indicators
The diagnostic portion of the DXPT1 board contains eight DIP switches, eight green LEDs, and a “clear”
pushbutton for clearing functions. Set the DIP switches to...

4.2 Requesting Cold Start Information
When the DXP-T1 system is turned on, internal self-tests are run to determine the condition of the
system. When you use this request, you are asking the system to provide you with the results of these
tests. Upon making the cold start information request, the system verifies the following.
·operating mode is superframe (SF) or extended superframe (ESF),
·FDL daughterboard (used for ESF) is installed on the T1 board and okay or not installed (or defective),
·channel...

4.3 Requesting Information On Received Signal Strength
When you use this request, you are asking the system to provide the signal strength of its received signals.
Upon making the received signal strength request, the system supplies you with the following information:
·the range in dB of the received signals.
4.3.1 Setting The DIP Switches For Received Signal Strength Information
Set the DIP switches as shown in the following table. Switch 1 is the top switch. When the switch is
moved to the right, it...