AC38A OPTO 22, AC38A Datasheet - Page 3

• Manufacturer Part Number: AC38A
• Description: Computers, Interface Cards
• Manufacturer: OPTO 22

Specifications of AC38A

• Peak Reflow Compatible (260 C): No
• Leaded Process Compatible: No
• Features: High-Speed RS485 Repeater, 120VAC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

ADAPTER CARDS
TRADITIONAL
STANDALONE
DATA SHEET
page 3/14
Form 519-100915
INTRODUCTION
The AC38 is an optically isolated 2-wire to 2-wire RS-485 repeater. The AC38 can operate at up to 115.2 KBd and is completely independent
of parity, stop bit, and data word size considerations. The AC38 has three connection ports; the host RS-485 port, the host RS-232 port, and
the remote RS-485 port. The remote RS-485 port is always a 2-wire connection; the host RS-485 can be used in 2-wire or 4-wire mode. The
host RS-232 port allows an interface with a maximum baud rate of 38.4 KBd; this interface will echo any data transmitted out of it, and it
will receive communication coming from either the HOST or REMOTE RS-485 ports provided it does not exceed 38.4 KBd.
While the AC38 is primarily an RS-485 repeater, it can also perform other convenient functions.
These are:
RS-485 REPEATER
The AC38 may be used simply as an RS-485 communications line repeater. When used in this manner, it is typically the last drop of one RS-
485 link and the first drop of another. The AC38 will transfer data from one link to the other, amplifying the signal in the process. Up to 3,000
feet of cable and 32 drops are permitted on each RS-485 link. Electrical isolation exists between the two links.
RS-485 ‘T-BRANCH’ OR ‘STAR’ ADAPTER
The AC38 also allows RS-485 communication links to be wired in a ‘T’ configuration. By making an AC38 one drop in the middle of an
RS-485 link, data can be transferred to and from a separate communication.
RS-232 TO RS-485 ADAPTER
The RS-232 port is designed to connect directly to an IBM AT RS-232 serial COM port, allowing it to be the host (master) of an Opto 22
Remote I/O Bus. The AC38 will convert the RS-232 signal to RS-485 while maintaining electrical isolation between the two links.
NOTE: The RS-232 port will automatically echo-back any data transmitted out of it, and it will receive communication coming from either
the HOST or REMOTE RS-485 ports provided it does not exceed 38.4 KBd.
Opto 22 • 43044 Business Park Drive • Temecula, CA 92590-3614 • Phone: [phone] • (800) 321-OPTO • Fax: [phone] • www.opto22.com
Inside Sales: (800) 321-OPTO • Product Support: (800)TEK-OPTO • [phone] • Fax: [phone] • E-mail: [e-mail]