User`s manual

Technical Description

The CyberResearch, Inc. COML 106U provides a PCI interface adapter with an additional asynchronous serial

port providing a versatile interface, field selectable as RS-232 for modems, printers and plotters, as well as

RS-422/485/530 for industrial automation and control applications.

The COML 106U utilizes the 16850 UART. This chip features programmable baud rates, data format,

interrupt control and a 128-byte input and output FIFO. The COML 106U also supports the Oxford

Semiconductor 16C950. This chip features the same FIFO, and automatic RS-485 driver enable capabilities as the

16C850 and the ability to receive a clock for isochronous communications.

Isochronous Communications

Webster's New Collegiate Dictionary defines synchronous as "recurring or operating at exactly the same period."

The majority of the serial buses in use today operate asynchronously, that is, "not synchronous" or more literally,

not clocked. The same dictionary defines isochronous as "uniform in time; having equal duration; and recurring at

regular intervals." In this implementation of serial communications, isochronous is defined as asynchronous framing

(i.e. start, stop and parity bits) with the addition of a clock signal. This scheme allows for much higher data rates

and the use of digital lines (i.e. ISDN, T1) where a clock is supplied for data multiplexing.

Connector Pin Assignments

RS-232 Signals (DB25 Male)

Signal Name Pin # Mode

GND Ground 7

RD Receive Data 3 Input

CTS Clear To Send 5 Input

DSR Data Set Ready 6 Input

TXC Transmit Clock 15 Input

RXC Receive Clock 17 Input

DCD Data Carrier. Detect 8 Input

RI Ring Indicator 22 Input

TD Transmit Data 2 Output

RTS Request to Send 4 Output

TSET Transmit Signal Element Timing 24 Output

DTR Data Terminal Ready 20 Output

Note: These assignments meet EIA/TIA/ANSI-232E DTE

Technical Note: Please terminate any control signals that are not going to be used. The most common way to do

this is connect RTS to CTS and RI. Also, connect DCD to DTR and DSR. Terminating these pins, if not used, will

help insure you get the best performance from your adapter.

COML 106U(-X)-D25 CyberResearch

Serial Communications