---
name: "cbus"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/cbus"
---

# cbus(4)

NEC PC-9801 extension board slot bus

## NAME

**cbus** – NEC PC-9801 extension board slot bus

## SYNOPSIS

**cbus0 at mainbus0**

## DESCRIPTION

**cbus** is a bus interface of "NEC PC-9801 extension board slot" (so-called "C-bus" in Japan) on LUNA-88K2. The original LUNA-88K does not have this slot.

## LIST OF DEVICES

The devices currently supported on **cbus** are:

- [ne(4)](/ne/4.md)

  Allied Telesis CentreCOM LA-98 series

- [necsb(4)](/necsb/4.md)

  NEC PC-9801-86 sound board

- [pcexmem(4)](/pcexmem/4.md)

  NEC PC-9801 extension board slot

- [pcmcia(4)](/pcmcia/4.md)

  PCMCIA (PC Card) support

## SEE ALSO

[intro(4)](/intro/4.md)

## HISTORY

The **cbus** bus interface first appeared in OpenBSD 5.7.