Minicom Advanced Systems CMG-DCM manual

Operator's guide

command pppd to establish these links. pppd is a versatile program, which uses command-line options to specify the type of PPP link required. These options are fully described in the Linux documentation for pppd.

The serial.x.ppp box allows you to specify pppd options to use on this serial port. Options which you wish to apply to all serial ports running the ppp service should be placed in the /etc/ppp/options file (see “options” in Section 4.4.)

serial.x.service : How the DCM will use each serial port. There are five options:

•getty : The module will use this port to listen for logins from a connected computer. Once logged in, the user will have direct command-line access to the DCM's Linux operating system.

•mgetty : The module will use this port to listen for logins over a connected serial modem. Again, a logged-in user will be presented with the DCM's Linux command line.

•mgetty-r : The module will use this port to listen for logins over a connected serial modem which is operating in raw mode (i.e. which does

not support the standard AT modem commands.) This option in runs the Linux command mgetty -r. A port running the mgetty-rservice will also listen for incoming PPP frames, and if it detects one will configure

the PPP link according to the /etc/mgetty+sendfax/login.config file (see “login.config” in Section 4.4.)

•

•

•

ppp: The module will use this port to provide a PPP link to a connected computer. Once set up on the computer, the DCM will appear as if on a local TCP/IP network. You can then log in to it using ssh or use its Web-based administration system, as well as receiving data.

Before a PPP link will function, you will need to specify the PPP options and (if using CHAP) provide a chap-secretsfile. This can be done through the DCM configuration interface: see “options” in Section 4.4

and “chap-secrets” in Section 4.4. Also see the Linux manual page for pppd(8) for an explanation of how PPP is implemented.

gcf_in : The module will use this port to communicate with a GCF- compatible digitizer.

gcf_out : The module will use this port to send GCF data directly to the connected device as it is received. A number of programs are available for PCs which handle incoming GCF data streams, such as Scream!, Antelope, and Earthworm. The DCM transparently merges all incoming data streams, so if you are using Scream!, you can also configure and

December 2005 45