Case Communications syncro 1496, Reference Manual

Page: 94 / 192

7.5 Analogue Parameters
The command is:
''S Display analogue parameters
Analogue parameters give information on the quality of the line over
which the modem is transmitting data. These parameters are derived from
the performance of the modem, and provide an indication of the
line/modem characteristics. They should not be taken as calibrated
measurements.
Note: Unless you are familiar with the data given by the analogue
parameters, you should not contact your communications network provider
until you are confident that a line problem exists.
Analogue parameters can only be displayed once the modem is trained and
receiving valid carrier from the remote modem. Any attempt to access
them with the modem off-line (or during training) will result in the
message
ERROR being returned.
Analogue Parameters are displayed in the following format:
Local Modem Analogue Parameters
01 Rx Level –20 dBm
07 Round Trip Delay 10 ms
08 Far End Echo –84 dBm
09 Phase Roll 0 Hz
11 EQM Value 0000
12 Signal Quality 1
13 Signal Noise 44 dB
14 Estimated BER <10
-8
An explanation of the parameters displayed is as follows:
01 Receive Level:
This is the level of the received carrier as seen by the modem. An
attenuation figure for the communications line can be calculated
using this information. Normally, in the UK, modems on leased lines
transmit at –13 dBm, and on the PSTN at –9 dBm.
Example: Receive level is –20 dBm. The remote modem is
transmitting at –13 dBm, therefore the attenuation is –20 minus –13
= –20 +13 = –7 dBm (a loss of 7 dBs).
X450-310851 Issue 2 7-8 Rev.0