Craystone UK - OCTOBUS Technical Page (page22)

octobus_technical

Click on a button for the relevant information

oct.jpg (8360 bytes)

The OCTOBUS four and eight port multi-user serial expansion cards offer a flexible and cost effective solution to providing multiple user access to a host computer system. The OCTOBUS range provides solutions with excellent value without compromising quality or service.

General Information

The OCTOBUS serial cards offer multiple 16550 RS-232D asynchronous communications with a minimum of
four serial ports to a maximum of eight per card.

In operation the COM ports will behave as any normal COM port.

Each card has individually selectable Baud rate of up to 56K baud, and connection to the outside world via
standard RJ12 connectors.

Ports one to seven support software handshake XON-XOFF and hardware handshake lines RTS and
CTS/DSR. Port eight only supports XON-XOFF.

A choice of five interupt settings are available; IRQ2, IRQ3, IRQ4, IRQ5 and IRQ7.

Each model has up to four address sets which may be chosen. Each set consists of eight port addresses and one status register address.

The status register can be set to BCD or BIT format, so the card is flexible for a variety of O/Ss.

Up to 4 cards may be installed into a PC (subject to the availability of interupts and addresses)

Technical Specification
Channels	4 or 8 ports
Controller	NS 16450 Compatible Standard
Size	Half Card
Data Speed	From 50 to 38,400 BAUD
Connectors	4 or 8 RJ11 (6 way)
Voltages	Levels are to EIA RS232D
Pin Layouts	Pin 1 - Ready to send	Pin 4 - Receive (Rx)
	Pin 2 - Ground	Pin 5 - Ground
	Pin 3 - Transmit (Tx)	Pin 6 - CTS/DSR

Octobus Set Up
There are three sets of jumpers on the OCTOBUS which need to be set prior to installing the card within a PC. The following three sections explain how to set the IRQ, Address Set, and Status Register. The General Set Up Table, located below the three sections, gives examples of set up information relating to particular operating systems.

View the OCTOBUS card with the chips visible and the RJ12 sockets to the right. A representation of the jumpers is shown below.

IRQ Set Up
The first jumper group on the left of the card is the interupt jumper. It can be set to one of five positions, IRQ 2,3,4,5, or 7. Some operating systems do require a specific IRQ.
It may be necessary to disable COM1 if IRQ4 is selected, COM2 if IRQ 3 is selected, and LPT1 if IRQ 7 is selected, to avoid I/O conflicts.
The diagram on the right shows the various IRQ settings.

irq_jumpers_drawing
A rectangular block represents a jumper.

Address Set set-up
The next jumper from the left of the card is the Address Set jumper. This selects the address range for the board's operating chip. The diagram on the right shows the jumper selections for the four possible address set ups.

address_jumpers_drawing
A rectangular block represents a jumper.

Status Register Set Up
The furthest jumper from the left of the card is the Status Register jumper. This selects whether your card will be set up in BCD mode (left position) or BIT mode (right position). The diagram on the right shows the two possible positions available.

status_jumpers_drawing
A rectangular block represents a jumper.

General Set Up Table
Chip	Address Set	O/S	Card No.	Port Address Range	Status Register	Status Mode	IRQ
A820	SET 1	PICK	1	198H-1D7DH	188H	BIT	3
A820	SET 2	PICK	2	298H-2D7H	288H	BIT	4
A825	SET 1	PICK	3	118H-157H	108H	BIT	7
A825	SET 2	PICK	4	218H-25FH	208H	BIT	2
A860	SET 1	NT	1	100H-13FH	140H	BIT	Any
A860	SET 2	NT	2	180H-1BFH	1C0H	BIT	Any
A860	SET 3	NT	3	230H-26FH	270H	BIT	Any

For example: The diagram below shows the settings for an OCTOBUS with A820 chip, IRQ 3.

If you didn't enter our website via the index page. Please click here