EXP-485 RS485 Adapter • RS485 interface option for all Ampro serial ports RS485 CABLE POWER CONNECTOR CONNECTOR RS232 INPUT RS485 RJ11 MODULAR CONNECTORS The RS485 Adapter offers a low cost, easy-to-use signal levels. Connection to the RS232 serial port communications and networking interface that is of any Ampro CoreModule™ CPU, Little Board™ ideally suited to a wide variety of embedded CPU, or MiniModule™ expansion product is direct, applications requiring low speed data transfer using the included RS232 interface cable. The between two or more CPUs. adapter may be mounted easily using four spacers. Many interconnection possibilities exist, including The RS485 “bus” can interface with up to 4,000 both simple two-system and complex multidrop feet of twisted pair cable, used as a half- duplex configurations. RS485 can be used instead of bidirectional data bus. Data direction is controlled more expensive Ethernet or Arcnet LANs, when by the RS232 serial port’s RTS signal. Connection data throughput requirements are modest. Some to the RS485 “bus” is via one or more of the capabilities supported by readily available RS485 adapter’s three interface connectors, which are software include disk drive and printer sharing, wired in parallel with each other. Two four-pin sending data and messages between systems, RJ11 modular connectors facilitate the use of synchronization of real-time clocks, and “bridging” standard and inexpensive cables and accessories. with other LANs, including Ethernet, Arcnet, and The RJ11 connectors provide redundant data other RS485 based topologies. connections, for maximum data integrity. A third RS485 interface connector (a 10-pin dual row Physically, the RS485 Adapter consists of a short header) is provided as a convenience for systems (10 in.) RS232 interface cable, plus a tiny where RJ11- type connections are not desired. (2.1 x 1.7 in.) board that contains the circuitry required to convert between the RS232 and RS485 56 Ampro Computers, Inc. • 4757 Hellyer Ave., San Jose, CA 95138 • Tel. (408)360-0200 • Fax (408)360-0222 • sales@ampro.com SPECIFICATIONS EXP-485 GENERAL Serial port compatibility: usable with all Ampro RS232 serial ports RS232 “HOST” INTERFACE • Maximum data rate: same as that of the associated RS232 serial port • RS232 port signal utilization: • — TxD and RxD connect to half-duplex bidirectional data — RTS controls data direction (high = send) — RxD monitors RS485 line status during send mode RS232 port interface cable specifications: • — Typical cable length (included): 10 in. (254 mm) — Maximum recommended cable length: 3 ft. (915 mm) Transmission protocol: half-duplex bidirectional communication over a single 2-wire pair RS485 “BUS” INTERFACE • Interface connectors (all wired in parallel): • — Two RJ11 connectors — One 10-pin header connector Cabling specifications: • — Usable with most twisted pair cable — Recommended cable impedance: 100 ohms — Maximum cable length per “bus”: 4,000 ft. (1.2 KM) — Maximum number of nodes per “bus”: 50 — Integral terminator: 100 ohm resistor, jumper enabled MECHANICAL SIZE 2.1 in. x 1.7 in. x 0.8 in. (54 mm x 43 mm x 21 mm) • Requirements (typical with two 100 ohm terminators): POWER • — Receive mode: 25 mA at 5 VDC ±5% — Transmit mode: 85 mA at 5 VDC ±5% ENVIRONMENTAL 0° to 70° C standard temperature • –40° to +85° C extended operating temperature (available by special order) • 5% to 95% relative humidity, non-condensing • Storage temperature: -55° to +85° C • Weight (adapter, only): 0.6 oz. (17 gm) • NOTE: Contact Ampro regarding custom configurations and special order options. For ordering information and pricing please refer to Ampro Ordering Guide. THE EMBEDDED SOLUTIONS PROVIDER™ Ampro Headquarters: 1 (800) 966-5200 • www.ampro.com 57