2.4.1 Rate selection guidelines
Before setting the data rate you should have known the performance of the
line the modems are intended for. If the line performance is unavailable,
apply the following technique to select the proper data rate:
•
Measure resistance of the line. To do this, make short-circuit on either
line side and attach an ohmmeter to another one. Then determine a
maximum rate providing reliable communication by table 2.
•
Switch carefully the dial to the required position with a screwdriver.
Reboot both modems to activate the new settings. Link activation
takes up to 2 or 3 minutes to succeed.
•
If the link is not activated (the DSL LINK LED is not getting light) during
the mentioned time, set a smaller value on the rate dial and do the next
attempt to activate the link.
•
If you can't get the link activated, consider to use console management
mode (Chapter 3). In this mode you can try to succeed by varying the
line coding (Chart 1) as well.
2.4.2 Automatic rate selection
Set the SET2 DIP switch to “ON” position for each modem to enable DSL
automatic rate selection (Line Probe). Automatic rate selection operates in
the range conforming to ITU-T G.991.2 within 192 to 2048 kbps with
ТСРАМ16 line coding only. Besides, the RATE dial sets the upper limit for
the rate. If the modems have different dial settings, the rate is limited by the
least value.
2.5 Е1 interface setup
2.5.1 Connecting Е1 interface
Equipment attached to the modem is required to have a balanced Е1 port,
typically implemented as an RJ-45 socket. The interface uses 2 loops, one
to receive and another to transmit the data. Pins 1 and 2 are assigned to the
Е1 receiver input, pins 4 and 5 are assigned to the transmitter output (Table
17
