CHAPTER 5
SWITCH SETTING


5.1 Compatible Mode

The first two serial ports are referred to as COM1: and COM2: which are standard ports for IBM PCs. If the PCCOM 4 port RS422 adapter is configured to emulate two standard ports by setting two of the four ports to be compatible with COM1: and COM2:. This is called compatible mode.

5.2 Enhanced Mode

The PCCOM 4 port RS422 adapter may be configured to coexist with the two standard ports, adding four ports for a total of six. This is called enhanced mode. Under the enhanced mode, a maximum of two adapters can be added to the system, which provides eight additional ports for a total of ten.
 

5.3 Add two PCCOM 4 Port Adapters

A. Compatible with COM1: and COM2:


 Port
First
   Adapter		 COM1:
COM2:
3
4
Second
   Adapter		 5
6
7
8

B. Coexist with COM1: and COM2:

Port
Standard
    Port
 COM1:
COM2:
First
   Adapter
 1
2
3
4
Second
   Adapter
 5
6
7
8

5.4 Configuration for Dip Switch and Jumper

It is important to refer to the user manual supplied with your operating system to determine the correct configuration. Although we provide installation advice for various operating systems, it is not possible to cover all systems in this user guide. Please contact your supplier if you have any difficulties with configuration.

IMPORTANT: CARE MUST BE TAKEN IN SELECTING THE CONFIGURATION OF JUMPERS AND SWITCH TO ENSURE YOU DO NOT DUPLICATE SETTINGS OF OTHER EQUIPMENT ALREADY INSTALLED IN YOUR COMPUTER. DUPLICATION OF SETTINGS WILL RESULT IN A MALFUNCTION OF ONE OR BOTH DEVICES.

Please refer to the following settings for each switch and jumper block. If you are installing more than one board, do not duplicate jumper settings for any parameter.


1. I / O Address Selection

SWITCH 1,2: Select Compatible Mode or Enhanced Mode.






Default setting is in Enhanced mode (high address).


The mapping of I/O addresses to each channel are shown in below:




2. Interrupt Selection

SWITCH 3, 4, 5: Select interrupt mode



Global interrupt means all 4 ports use common IRQ and separate interrupt means each port uses individual interrupt. Default setting is in global interrupt mode and almost applications are used in global interrupt mode.


3. Select Wait State

JP2: Select Wait State




4. Interrupt
JP4 is used to select global interrupt. Short right side of JP4 means to select interrupt line of all channels.



In standard PC system, COM1 and COM2 generate interrupts on IRQ4 and IRQ3 respectively. The default setting is IRQ5 (enhanced mode / high address). We recommend you to set IRQ5 for first adapter and IRQ7 for second adapter. However, you may set any interrupt line according to your requirements.
 
Suppose you set SW3, SW4, SW5 to separate interrupt mode, then JP3 and JP4 are used to set interrupt for each port. Short right side of JP3 means select interrupt for port 2, short left side of JP3 means select interrupt for port 1. Short right side of JP4 means select interrupt for port 4, and short left side of JP4 means select interrupt for port 3.



If you set separate interrupt mode, then for each channel, you may select each interrupt separately. Please note that if compatible mode is selected, the COM1 and COM2 generate interrupt on IRQ4 and IRQ3 respectively.

5. J2 iumper

Always short pin 1 and pin 2.