Table of Contents
Advertisement
Chapter 3 – Software
Line Interfaces > Line 1 Setup > T1 PRI
Receive Sensitivity
This layer 1 parameter configures (tunes) the interface's receiver circuit. There are two choices to select from,
Short Haul Mode (-10db) and Long Haul Mode (-36 dB).
T1 signals are full duplex. A T1 digital interface generates and transmits a signal onto the line, while at the
same time it receives and recovers a signal from the line.
Short Haul Mode (-10db)
Setting the receive sensitivity to Short Haul Mode means the MultiAccess receiver expects the size of the
incoming signal to be between 0db and -10db. If the incoming signal is greater than 0db or if it's smaller than
-10dB, the interface will indicate a Red Alarm condition.
Long Haul Mode (-36db)
Setting the receive sensitivity to Long Haul Mode means the MultiAccess receiver expects the size of the
incoming signal to be between -10db and -36db. If the incoming signal is smaller than -36dB, the interface will
not be able to recover it and will indicate a Red Alarm condition. If the incoming signal is greater than -10dB,
depending on many variables (wave shape, jitter, dB level, cable quality, EMI, etc) erratic communication, bit
errors and other problems may or may not result.
Country
This allows you to select the country for which the equipment is operating in and needs to comply with.
Line Build Out (LBO)
This layer 1 parameter dictates the physical size (decibel level) of the T1 signal being transmitted by the
MultiAccess. Your choices are 0dB, -7.5dB, -15 dB & -22.5dB. 0dB is the largest size signal the MultiAccess
can transmit.
There are a number of variables as to when the Line Build Out setting should be changed. The primary factors
are, cable length, gauge and quality (twists per inch and shielding) and what size signal does the equipment
opposite to the MultiAccess want to receive from the MultiAccess. As the signal travels down the cable it
attenuates (becomes smaller and it's wave shape starts to change) - what size will it be at the other end of the
cable?
If the receiving equipment (for example a T1 card in a PBX on your premise) is connected to the MultiAccess
with a 6 foot cable, having the MultiAccess transmit at 0dB may be too hot (too large) of a signal for that device
to receive, so setting the Line Build Out to -15dB may be more appropriate.
Voice Channel Encoding -
This parameter automatically follows the Line Type selection, however
the user can change it from it's defaults. When the line type is set to E1, the PCM rule (Voice Channel
Encoding) will be set to A-law. When the line type is set to T1, this option will be set to u-law. The ability to
change this setting independent of the line type allows for flexibility in privately controlled closed circuit
networks.
MultiAccess Communications Server MA30120 User Guide
125
Advertisement
Table of Contents
