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.
2.5 Е1 interfaces setup
2.5.1 Connecting Е1 interfaces
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
6, figure 5). Other pins are not assigned. It is not necessary to recognize
polarity of the connection.
Table 6
Pin
Е1 circuit
1
R (Rx Tip)
2
Receive – (Rx Ring)
4
Tr (Tx Tip)
5
Transmit – (Tx Ring)
17
