User manual

CHAPTER 3 : FRONT PANEL AND MENU TREE
3.5 Detailed Description of the Menu Tree
3.5.1 STATUS MENU
Item Name Command Description
TX LEVEL = -XX
dBm
AT%S
Transmitted signal level. This value is equal to the " TX level"
of config modem. Normally, for the 2w leased line and the dial
line, the recommended value is between -10 and -13dBm. It
can be increased of in order to obtain a more satisfactory S/N
ratio (signal to noise ratio) by setting a higher level as possible,
but a saturation of the active transmission equipment should be
avoided. The Tx level level should be setting under -13dBm
while to operating V.34 mode.
RX LEVEL= -XX dBm AT%S
Received signal level. This value is the result of the line
attenuation from the transmitted signal. Normally, the RX level
of 2w leased line and the dial line is between -15 and -33dBm.
S/N. RATIO = XX dB AT%S
Signal to noise ratio. The bigger the S/N ratio, the better
quality of a line is. A higher operating speed needs a higher
S/N ratio. Normally, the S/N requirement of running 14400
bps should be more than 24 dB while to operate at 9600 bps,
a S/N better than 20 dB is required.
EQM VALUE=XXX AT%S
Eye pattern quality monitoring. This value represent the quality
of receiving signal.
F-SHIFT = XX Hz AT%S
Frequency-shift (offset). It is the shift of the carrier central
frequency caused by the transmission link. This shift normally
should be less than + / - 7 Hz. The smaller is better.
F F-SHIFT = XX Hz AT%S
Far end frequency-shift (offset). The frequency shift of the far
end received carrier signal. It normally should be less than +/-
7 Hz. The smaller is better. The value will not accurate once
level is too small from the remote site.
DELAY = XXXX ms AT%S
Round trip delay time. This delay is caused by a round trip of a
long distance line , especially in a satellite circuit. Usually,
round trip of a satellite link shall create a time delay of 0.5
second (500ms). The modem will accept a maximum time
delay of 1.2 seconds.
P JITTER = -X Deg AT%S Monitoring the phase jitter of the phone line.
F ECHO = -XX.X dB AT%S Far end echo. This echo is caused when the far end line
impedance is not matched. A smallest far end echo level is
always required. Normally,the far end echo level is between -
20 dB and -55 dB
DTE = XXXXX ASY
10
AT%S Indication of speed and data format of DTE. For examples:
DTE = 19200 ASY 10 stands for 19200 bps Asynchronous 10
bits in total bit length. DTE=14400 SYN means 14400 bps
synchronous.
RETRAINS = XXXX AT%S
Total retrain count. From the total retrain count, you will find
the total times of line interference occurred. This value will not
b
e cleared automatically unless pressing the "ENTER" key or
power off.
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