Specifications

NSTS 21000-IDD-760XD

6.10 RS-232C COMMUNICATIONS

The PGSC contains one RS-232C asynchronous serial I/O port that provides a communication

link between the PGSC and an external device. This is a standard serial port as defined in EIA

STD RS232C. This port is a 9-pin version compatible with an IBM PC-AT 9-pin serial port. For

RS-232C cable pin outs and description, see paragraph 7.2.1.

6.10.1 RS-232C Line Drivers/Receivers

The PGSC uses standard bipolar line drivers/receivers, the 1489 transmitter and the 1488

receiver. The 1488 line driver is capable of producing 14.8 mA current. Information regarding

the line drivers/receivers is readily available in published data manuals.

6.11 RS-422A COMMUNICATIONS

6.11.1 Quatech PCMCIA RS-422/485 Dual Channel Serial Adapter Card

The Quatech PCMCIA RS-422/485 interface is a standard Commercial off the Shelf (COTS)

PC Card 2.1 compliant Type II PCMCIA component which adds two fully independent

asynchronous RS-422 interfaces to the PGSC Flight Computer. The card uses a 16550 UART

with programmable baud rate and data formats. A maximum serial link of up to 4000 feet may

be realized. The RS-422 maximum baud rate is 115.2K. Consult the Quatech DSP-200/300

User’s Manual for additional information.

6.11.2 Sealevel ISA RS-422A Serial I/O ISO Communication Card

The Sealevel RS-422A Serial ISO Communication Card is a COTS “SEALEVEL” AT

compatible PC board (part number 3417). The ISO-com board uses a 16550 UART with

programmable baud rate and data formats. The board allows very long distance (5,000 ft. at

9,600 baud) communication with virtually error free differential drive characteristics. The ISO-

com board provides the PGSC with two ground isolated serial ports. NOTE: Certain

Expansion Unit configurations have one of the ports disabled. Consult the User’s Manual for

additional information.

6.11.3 RS-422 Adapter

The RS-422 Adapter is an in-house designed adapter allowing compatible communications

between a Quatech PCMCIA RS-422/485 Dual Channel Serial Adapter Card (SDG39129284-

301) and other compatible RS-422 communication devices. The adapter applies a termination

resistance of 100 Ohms across the Data input and Auxiliary input pins to help eliminate noise

from the channel line and allows interface with existing RS-422 flight cables. See figure 6-1 for

details