Technical data

3-12 Theory of Operation

• Communications with ETHERNET Version 1, Version 2, and IEEE 802.3

compatible controllers

• A transceiver that provides connection to “thin” ETHERNET cabling (Thin-

LAN) through a BNC type T-connector on the back panel

• A 15-pin, D-connector on the back panel that provides connection to standard

ETHERNET/IEEE 802.3 cabling (AUI) through a transceiver and transceiver

cable

• Support for simultaneous Domain routing and TCP/IP gateway service on a

single system or, in a shared mode, to all systems on an Apollo Token Ring

network

For systems that run in HP-UX Compatible mode, you can use the Boot ROM’s Inter-

face Conﬁguration Mode to set the following 802.3 LAN conﬁgurations:

• Select code 0 through 31

• Interrupt levels 3 through 6

For more information about using the Interface Conﬁguration Mode, refer to Appendix

An 801.3 LAN interface with a built-in media attachment unit (MAU) is part of the

CPU board. The shared memory area has the memory controller circuits, 16 KB of

memory, 64 nibbles of nonvolatile storage of the node address, and control, status, and

ID registers. Multiplexing of DIO-II information and the 802.3 LAN chip set is also

part of the controller circuit.

An AUI (attachment unit interface) connector enables connections to an external

MAU. The MAU circuits used with the ThinLAN connector are not used. A replace-

able fuse, located behind the AUI connector, protects the LAN circuits from MAU

faults.

LED and Service/Normal Interface

This interface controller interfaces the LED board to the DIO II bus.

Audio Output Generator (for HP-UX Compatible Systems)

The Audio Output controller drives an external speaker with programmable volume,

duration, and frequency. The controller defaults to an internal speaker if no external

speaker is connected.

SCSI Interface

A Series 400 system incorporates an industry standard Small Computer Systems Inter

face (SCSI) that allows the connection of peripherals (such as Winchester and Magneto

Optical disks, magnetic tape drives, and cartridge tape drives) to the system.