Technical data

Conﬁguring Serial Lines

3.3 Setting Up a SLIP Interface

3.3.1 Setting Up Hard-Wired SLIP Lines

To conﬁgure SLIP with hard-wired lines, follow these steps:

1. Establish a physical connection. Plug in a serial cable between the two host

systems or ensure that they are both cabled to opposite ends of a leased line.

2. Obtain an IP address if necessary.

3. Conﬁgure the SLIP interface. Enter the SET INTERFACE command with the

/HOST and /SERIAL_DEVICE qualiﬁers, which are required.

3.3.2 Setting Up SLIP Dialup Lines

You can conﬁgure either a terminal server port or an OpenVMS system to answer

dialin calls.

Follow these steps:

1. Conﬁgure the appropriate settings for the terminal port to which you will

connect. Begin a dialog of dialing (or answering) commands with your

modem. The speciﬁc required commands depend on the type of modem you

are using.

For example, to prevent the modem from hanging up when you exit the DTE

session to bring up the SLIP line, enter the following command:

$ SET TERMINAL TTA2 /PERMANENT /MODEM /NOHANGUP

To disable interactive logins on the line, enter the following command:

$ SET TERMINAL TTA2 /PERMANENT /NOTYPEAHEAD

Any SLIP data that arrives before you enter the SET INTERFACE command

is ignored. Otherwise, this command triggers the creation of a new interactive

To enable interactive logins after a user sends a Break, enter the following

command:

$ SET TERMINAL TTA2 /PERMANENT /NOAUTOBAUD /SECURE_SERVER

2. Conﬁgure the modem. Enter the appropriate commands to dial the telephone

and establish communication.

3. Unless you are setting up a SLIP line between two hosts running TCP/IP

Services and plan to use the /FLOWCONTROL qualiﬁer at both ends, disable

modem recognition of XON and XOFF characters. (If SLIP packets have

Ctrl/S and Ctrl/Q characters embedded in them as data, you must prevent the

modem from trying to interpret these characters.)

Either use hardware ﬂow control or disable ﬂow control entirely. The

following examples disable all ﬂow control.

• With a DECmodem V32 in AT command mode, set the following values:

AT%F0

— No speed buffering ﬂow control

AT%M0

— Disable speed buffering (optional)

• With a DECmodem V32 in DMCL mode, set the following values:

SET P2/SBU

SET P1/SBU

prompts appropriate_answers

Conﬁguring Serial Lines 3–11