The x21IfTable contains information relating to the
interfaces found on the system. Each entry corresponds to
a connected X21 interface. Entries can only be added or
deleted by the system.
Creating entries: Entries are created by the system
only when a new X21 module is installed.
Deleting entries: Entries are removed by the system
after the appropriate X21 module is removed.
The value of IfLeads has influence on the state of the
physical layer (L1State). When configured as
IfLeads=enabled(1), the state of the physical layer
depends on the signals of the X.21 interface pins
`Indication' and `Control'. When configured as
IfLeads=disabled(2), the state of the physical layer
stays always up.
The layer 2 mode. This value has influence on the
HDLC address field (first byte of a HDCL frame). When
configured as DTE(1) the address in a command frame is
0x01, when configured as DCE(2) it is 0x03. For
response frames it is vice versa. When configured as
AUTO(3), layer 2 is set to the same mode like L1Mode is