Using The Scs Without Dialup Modems; Situations Where Dialup Modems Are Not Used - Lantronix SCS Reference Manual

Additional Remote Networking

5.6 Using the SCS Without Dialup Modems

The SCS may be configured to allow Remote Node and LAN to LAN functionality without using modems;
dial-on demand features will be ignored.

5.6.1 Situations Where Dialup Modems Are Not Used

There are four primary situations in which the SCS may be used without modems:
Direct connections
Statistical multiplexors
Synchronous leased line
Analog leased lines
5.6.1.1 Direct Connections
Two buildings may be linked with a serial cable. Two SCS units may use the serial cable to connect two
networks together.
5.6.1.2 Statistical Multiplexors
Two locations may have statistical multiplexors (commonly called stat-muxes) in place. These stat-muxes
may be used to connect to SCS units. A series of commands may have to be sent to the stat-mux to connect
to the remote SCS; chat scripts make sending these commands easy and relatively error-free.
See Chat Scripts on page 5-3 for more information.
Note:
The SCS assumes an 8-bit data path. If you are using SLIP, all characters must be sent and received
unchanged by the intervening communications equipment. PPP has a feature called ACCM which causes
the SCS to avoid sending user-specified control characters. If the equipment connecting the SCS cannot
send certain control characters, configure PPP and ACCM on the SCS port.
ACCM is discussed in detail in Character Escaping on page 7-1
Note:
5.6.1.3 Synchronous Leased Lines
The SCS supports asynchronous serial connections. Many leased lines are synchronous. Devices which
convert between synchronous and asynchronous serial signals exist, but they may result in some
performance loss. The current SCS units are not always the best solution for synchronous leased line
applications.
5.6.1.4 Analog Leased Lines
To use an SCS with analog leased lines, the modems on each end of the connection must support leased line
mode and should use asynchronous serial communication.
See your modem's documentation to configure the modem for leased line mode.
Note:
Two SCS units are linked with a serial cable.
Multiplexors (stat-mux) allow multiple serial lines to run over a single
leased line. The stat-mux must support asynchronous serial
communication.
Lines are leased from the telephone company and dedicated to
synchronous serial communication between two fixed locations.
Analog lines are ordinary telephone lines leased from the telephone
company and used in conjunction with standard modems. The modems
must have leased line capabilities.
5-13
Using the SCS Without Dialup Modems