D-Link DI-1750 Reference Manual page 32

How to connect with V.92 MODEM or those that doesn't support V.42bis
Since the chip of our MODEM card can not support the protocol beyond V.90, if you want to connect
with some V.92 MODEM of other company, the connection with the V.92 MODEM may be failed.
(However, you can still dial from the V.92 MODEM to the router.). User can write an initializing script,
add "AT&H4 OK" into it. Then, the network mode of MODEM will be adjusted to V.32bis multimode and
the connection with V.92 MODEM can be set up successfully. You can also use this method when you
can not create connection with other older MODEM. What's more, if the MODEM of peer does not
support V.42bis encapsulation protocol, you can close the encapsulation function by adding "AT%C0
OK" into the initializing script. The network mode and command type are listed below:
Command
AT&H0
AT&H1
AT&H2
AT&H3
AT&H4
AT&H5
AT&H6
AT&H7
AT&H8
AT&H9
AT&H10
AT&H12
3.12.2 Configuring Logical Interface
In this section we will introduce how to configure the logical interface that include following content:
1. Configuring a Null Interface
The D-Link router supports a "null" interface. This pseudo-interface functions similarly to the null
devices available on most operating systems. This interface is always up and can never forward or
receive traffic. The only interface configuration command that you can specify for the null interface is no
ip unreachable. The null interface provides an alternative method of filtering traffic. You can avoid the
overhead involved with using access lists by directing undesired network traffic to the null interface.
To specify the null interface, use the following command in global configuration mode:
Command
interface null
Input the command "interface", it will prompt:
(00)FastEthernet
(01)Ethernet
(02)Serial
(03)Async
(04)Null
.....
Please Input the code of command to be excute(0-10): 4
Input 4, choose the item "Null", it will prompt:
Please input a interface name: null0
Input "null0".
Network mode
V.92 multimode
V.90/V.34
V.34 multimode
V.34 only
V.32bis multimode
V.32bis only
V.22bis
V.22
Bell 212
Bell 103
V.21
V.23
Enter the status of null interface configuring
FastEthernet interface
Ethernet interface
Serial interface
Asynchronous interface
Null interface
Model Name
Function
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