Rs-232 Interface (Com1~Com2); Rs-232/422/485 Interface (Com3~Com4); 16C550 Uarts With 16-Byte Fifo Standard; Rs-422/485 Detection - Advantech UNO-3074 User Manual

2.2 RS-232 Interface (COM1~COM2)

The UNO-3074 offers two industrial standard RS-232 serial communica-
tion interface ports: COM1 and COM2. Please refer to Appendix A.4 for
their pin assignments.
The IRQ and I/O address range of COM1 and COM2 are listed below:
COM1: 3F8

2.3 RS-232/422/485 Interface (COM3~COM4)

The UNO-3074 offers two industrial RS-232/422/485 serial communica-
tion interface ports: COM3 and COM4. Please refer to Appendix A.5 for
their pin assignments. The default setting of COM3 and COM4 are RS-
422/485. (Please refer to section 2.3.4 for how to determine RS-232 or
RS-422/485)

2.3.1 16C550 UARTs with 16-byte FIFO Standard

Advantech UNO-3074 comes with 16C550 UARTs containing 16 bytes
FIFOs.

2.3.2 RS-422/485 Detection

In RS-422/485 mode, UNO-3074 automatically detects signals to match
RS-422 or RS-485 networks. (Refer to section 2.3.5)

2.3.3 Automatic Data Flow Control Function for RS-485

In RS-485 mode, UNO-3074 automatically detects the direction of incom-
ing data and switches its transmission direction accordingly. So no hand-
shaking signal (e.g. RTS signal) is necessary. This lets you easily build an
RS-485 network with Data+, Data- and Ground. More importantly, appli-
cation software previously written for full-duplex RS-232 environments
can be maintained without modification.
, IRQ4 COM2: 2F8
H
, IRQ3
H
13 Chapter 2