Creating Device Files for Serial Ports

You need to create device files in the /dev directory for serial ports. Each serial port used for pppd may require one to four device files. Depending on the hardware attached, you may need files for dial-in, dial-out, or direct connection.

Use the System Administration Manager (SAM) to create device files. Creating the device files with appropriate minor numbers is important.

The following is an example of an entry in /dev for the device tty0b1, a dial-in modem with hardware flow control enabled.

major number = 1
minor number = 0x000012

The minor number corresponds to the template 0xIIPPHM, which is resolved as follows:

II	Two hexadecimal digits (8 bits) to indicate the instance of the serial interface. The instance of the serial interface is determined by running the program ioscan -f and looking in the "I" column. On a series 700, port A will generally be 0 and port B will generally be 1.
PP	Two hexadecimal digits (8 bits) to indicate the port number of this device on the serial interface. On a Series 700 serial port, this will always be 0.
H	One hexadecimal digit (4 bits) to control diagnostic access and hardware flow control (HP J2094A only). Bit 0 controls RTS/CTS hardware flow control. bit 0 = 0 disables the hardware flow controlbit 0 = 1 enables the hardware flow control
M	One hexadecimal digit (4 bits) to determine port access type. Values for each bit are: bit 3 = TI/ALP bit 2 = 0 means simple protocol (U.S.A.) bit 2 = 1 means CCITT protocol (Europe) bits 0 and 1 = 00 direct, 01 dial-out modem, 10 dial-in modem, 11 unused

You can also use the mknod(1M) command to create device files, for example:

mknod /dev/ttyd10 c 1 0x000001 #dial-in

The termio(7) man page describes how to derive the minor number of the device file for dial-in, dial-out, and direct connections. Major and minor numbers may be different from system to system. See termio(7) for more details about configuring a serial device.

Creating Device Files for Serial Ports

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