ADC MM702G, User Manual

Page: 69 / 168

Chapter 6: Configuring DSL Parameters
MM701G and MM702G User Manual 61
•
Annex-B for operating conditions typically found in the European implementation
of G.shdsl. This is the default mode for the MM701G modem.
•
Auto
for automatically negotiates the Annex A or B standard by which this modem,
and the device to which this modem is attached, can operate. This is the default
mode for the MM702G modem.
•
Annex-B_ANFP for operating conditions that include the Annex B standard with
Access Network Frequency Plan Pulse Spectral Density (PSD) mask.
•
Auto_ANFP
for automatically negotiating the Annex A or B standard with Access
Network Frequency Plan Pulse Spectral Density (PSD) mask.
Startup Margin
The target signal-to-noise margin, in decibels, that the modem must achieve with a
BER of 10
-7
or better to successfully complete synchronization. The default margin
value is 6 dB. A lower margin may result in a higher data rate, but it can increase noise
on the line. Possible values are
-10dB through 10dB , or to completely Disable the
margin.
Data Rate (kbps)
Data rate determines the maximum transmission rate, in kilobits per second, up to
which the modem can negotiate and synchronize with another device (modem or a
DSLAM) to which it is attached. When the
Bit Rate Mode
( page 62 ) is set to
Fixed,
the
range of values are (ADC modems comply with the standard G.shdsl data rate range):
•
for the MM702G modem, 384 kbps to 4608 kbps, in 128 kbps increments (default
value is 4608)
• for the MM701G modem, 192 kbps to 2304 kbps, in 64 kbps increments
Rates down to 64 kbps are supported only when operating in single-pair,
point-to-point mode with another ADC modem. (see
Chapter 7 , “Implementing a
Point-to-Point LAN Extension” ).
When the
Bit Rate Mode
( page 62 ) is set to
Adaptive
for an MM701G (
Adaptive
is
MM701G default value) or for an MM702G set to
Single Wire Pair Mode
only (see
below)
,
this field is automatically set to
Adaptive
. An MM702G in
Dual Wire Pair Mode
cannot be used in
Adaptive Bit Rate Mode
.
Wire Pair Mode
Indicates whether the G.shdsl modem is operating in a two-wire mode ( Single ) or a
four-wire mode ( Dual ). For the MM701G modem, Single mode is the only setting
available. For the MM702G modem, you can select either Single or Dual mode and
Dual mode is the default.