User Manual

9-1
9: Modems
This chapter discusses how to configure your modem and the SCS to work together.
If you have an SCS200, you can configure a supported modem card to form PPP dialup connections.An
installed modem card on the SCS200 can be accessed using port number 3. Because the SCS does not
support PC card hot swapping, you must reboot the SCS anytime you remove a modem card.
Note: For a current list of supported modem cards, see the Lantronix web site,
www.lantronix.com.
This chapter is divided as follows:
◆ Setup and Wiring, page 9-1, describes any necessary physical connections.
◆ Modem Speeds, page 9-2, covers both a modem’s serial speed and line speed.
◆ Modem Profiles, page 9-2, shows how the SCS can use a modem profile to interact properly with a
modem.
◆ Modem and SCS Interaction, page 9-8, describes the interaction between an SCS and modem during
incoming and outgoing calls.
◆ Terminal Adapters, page 9-12, discusses the additional configurations necessary when using an ISDN
Terminal adapter instead of a modem.
◆ Caller-ID, page 9-12, shows the commands that will provide the SCS with Caller-ID functionality.
◆ Examples, page 9-13, gives examples of how to configure the modem profiles.
◆ Troubleshooting, page 9-16, suggests solutions for any difficulty you may encounter with your
modem configuration.
9.1 Setup and Wiring
Communication devices (modems, printers, servers, etc.) are divided into two types: DTE (Data Terminal
Equipment) and DCE (Data Communications Equipment). DTE and DCE are designed to work together,
much as a male connector works with a female connector. The SCS is a DTE device. Modems are DCE
devices. This means that they use opposite signals; the SCS uses a particular signal to send data, and the
modem uses that same signal to receive data.
Some devices that the SCS will connect to (such as printers) are DTE devices. Transmitting data between
two DTE devices requires the use of a null modem cable to swap the signals; for complete wiring
instructions, refer to the Pinouts appendix of your Installation Guide.
The SCS must be wired to the DCD pin on your modem. See the Pinouts appendix of your Installation
Guide for complete wiring information.
Note: For more information, see Serial Signals on page 8-20.