ADDCOM(4) | Device Drivers Manual | ADDCOM(4)

# NAME

`addcom` — multiplexing serial communications interface

# SYNOPSIS

`addcom0 at isa? port 0x108 irq 5`
`com* at addcom?`

# DESCRIPTION

The `addcom` driver provides support for Addonics FlexPort 8/S (and probably FlexPort 4/S) boards that multiplex together up to eight (or four) EIA RS-232C (CCITT V.28) communications interfaces.

Each `addcom` device is the master device for up to eight `com` devices. The kernel configuration specifies these `com` devices as slave devices of the `addcom` device, as shown in SYNOPSIS. The slave ID given for each `com` device determines which bit in the interrupt multiplexing register is tested to find interrupts for that device. The port specification for the `addcom` device is used to compute the base addresses for the `com` subdevices. The port for the interrupt multiplexing register is fixed, so it is doubtful that more than one `addcom` can be used in a machine.

# FILES

/dev/tty??

# SEE ALSO

com(4), intro(4), isa(4)

# HISTORY

OpenBSD support for `addcom` devices first appeared in OpenBSD 3.0.

May 21, 2008 | Debian