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CN-1108 Setup and Installation Manual
20
HPNA Switch Causes Inoperable or Malfunctioning PBX
There are many models of PBX worldwide today. Some PBX does not
correspond to certain standards when it comes to data transmission and FDM
(Frequency Division Multiplexing). Occasionally, when a HPNA switch is
installed on a system with a PBX, the PBX will cease to operate or the HPNA
switch will stop to function. The problem occurs due to the two devices use
FDM to allow the sharing of the telephone wire. When one device is attached to
the other, the impedance values begin to change the expected frequency responses,
rendering both devices making one of them unusable.
Solution:
Install an impedance matching filter to correct the frequency domain shift.
Depending on the frequency domain, type of PBX and amount of impedance shift
a filter may be needed between the PBX and the MDF or the CPE and Telephone
set equipment. Contact City-Net for information on impedance matching and
installation of CN-Filter and CN-Tester kits.
Standard Ethernet Frame Dropping
The CN-1108 will discard all illegal frames per Ethernet Standards:
1.
Packets Less Than 64Bytes
2.
Oversized Packets Larger Than 1522Bytes
3.
Bad CRC Frames
All Ports Show Collision and Flashing Link Lights
Reset the switch through the command interface or power cycle the unit.
Cannot Control Other CN Unit with Console Uplink
Be sure to set the first dipswitch to the ON by moving it to a downward
position and move the switch using a pen or a paper clip. Once completed, reset
both HPNA CN-switches.