Editing Acorn Archimedes A4000 (section)

=== Standard Ports ===

{| class="wikitable styled-table" style="width:85%; text-align:center;"
! Port !! Type !! Controller !! Features
|-
| Serial || 9-pin D-sub || 82C711 || 115200 bps maximum
|-
| Parallel || 25-pin D-sub || 82C711 || Bidirectional, EPP compatible
|-
| Mouse || 9-pin mini-DIN || IOC quadrature || PS/2 compatible with adapter
|-
| Keyboard || 5-pin DIN || 8051 MCU || PC/AT protocol
|-
| Video || 15-pin D-sub || VIDC1a || Analog RGB, separate syncs
|-
| Audio || 3.5mm jack || VIDC1a || Stereo line output
|-
| Network || Optional || Econet module || 250 kbps half-duplex
|}

The serial port implementation in the 82C711 provided full 16550-compatible buffering, improving reliability at high data rates compared to the unbuffered 6551 used in earlier models. The parallel port's EPP compatibility enabled connection to newer peripherals designed for PC systems.