- General Info
- Specifications
- Pinouts
- Images
- Troubleshooting
- Applications
DESCRIPTION
The ISO-485-PI9 is an industrial grade bi-directional port powered 2.5KV optically isolated RS232 to RS485 converter which converts a full-duplex RS232 port to a half-duplex two-wire RS485 port. A built-in data direction auto-turnaround feature automatically enables the RS-485 driver when data is present from the RS232 port, eliminating the need for software drivers, and making the device fully plug-and-play. The ISO-485-PI9 effectively protects connected devices from voltage surges such as lightning strikes, ground loop conditions and noise problems. The ISO-485-PI9 has a DB9 female connector on the RS232 serial port, and DB9 male connector on the RS485 port. Two separate terminal blocks, a rugged terminal block and a terminal block with built-in 120 Ohm termination are included with the product for maximum flexibility. The terminal blocks plug into the RS485 port, providing screw-lug wire terminations for the port. The unit is enclosed in a rugged ABS housing, and is powered from the RS232 data lines; no external power is required. This converter operates from 300 to 57,600 baud.
FEATURES
- Plug-and-Play (Device is Hot-pluggable)
- Two Terminal Blocks Included, One Rugged and The Other with Optional 120 Ohm Termination
- No Drivers Needed
- 2500V Isolation Protects RS232/RS485 Devices from Electrical Surges and Lightning Strikes
- 2500V Optical Isolation Also Eliminates Ground Loop and Noise Problems
- Port Powered: No External Power is Necessary
- Data Direction, Auto-turnaround, No Flow Control is Necessary
- Built-in 600W Surge and 15KV Static Protection
- 5 Year Manufacturer's Warranty
- RoHS 3, CE, FCC and REACH Certified

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5 Year Replacement Warranty!
DATASHEETS
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ISO 9001:2015 QUALITY MANAGEMENT

Our internationally recognized ISO 9001:2015 Quality Management System (Cert. No. 743003912) with a scope of Design, Sales, Distribution of Data Communication and IT Support Services was recognized and certified by TÜV Rheinland of North America known for its very demanding and stringent requirements. For more details see our Quality Policy.
COMMUNICATION | |
STANDARDS: | EIA/TIA RS-232C Standard and RS-485 Standard |
BAUD RATES: | From 300 baud To 57,600 baud |
CONNECTOR TYPES: | RS-232 Side: DB9 Female and RS-485 Side: either DB9 Male or 3-way Terminal Block |
DISTANCE: | RS-232 Side: 16 ft (5m) and RS-485 Side: up to 4000 ft (1.2km) |
MAX # OF CONNECTIONS: | 128 Connection Drops |
ELECTRICAL | |
POWER SOURCE: | Port Powered From RS-232 Data Lines |
OPTICAL ISOLATION: | 2500V (2500Vrms 1 min, AC) |
CURRENT CONSUMPTION: | Less Than 10 mA |
STATIC PROTECTION: | 15KV Electric Static Discharge (ESD) Protection |
SURGE PROTECTION: | 600W Surge Protection |
MECHANICAL | |
HOUSING: | Rugged ABS |
WEIGHT: |
With Terminal Block:
1.2oz (36 grams) Without Terminal Block: 0.8oz (24 grams) |
DIMENSIONS: |
With Terminal Block:
3.15 X 1.33 X 0.70
in (80.0 X 33.8 X 17.8 mm) Without Terminal Block: 2.47 X 1.33 X 0.70 in (62.8 X 33.8 X 17.8 mm) |
ENVIRONMENTAL | |
OPERATING TEMP.: | -40ºF to 185ºF (-40ºC to 85ºC) |
STORAGE TEMP.: | -40ºF to 185ºF (-40ºC to 85ºC) |
OPERATING HUMIDITY: | 5% To 95% - No Condensation |
QUALITY | |
PRODUCT SAFETY: | CE, FCC and RoHS Conformance Certified |
QUALITY MANAGEMENT: | Manufactured and Distributed to ISO 9001:2015 QMS |
RELIABILITY: | Low Failure Rate - 99+% Reliability Since Inception |
WARRANTY: | 5 Year Replacement Warranty |
RS232 SIDE DB9 Female
Signal | DCD | DTR | DSR | RTS | CTS | TX | RX | GND |
Pin # | 1 | 4 | 6 | 7 | 8 | 2 | 3 | 5 |
Function | TIED | TIED | TX | RX | GND |

RS485DB25 Male
Signal | D- | D+ | GND |
Pin # | 1 | 2 | 5 |
Function | D- | D+ | GND |



TERMINAL BLOCK SELECTION GUIDE
The ISO-485-PI9 comes with two terminal blocks for maximum performance and flexibility. One terminal block is a rugged terminal block which is sealed to provide protection from the elements and vibration. The other terminal block has a built-in 120 Ohm termination selectable by a jumper on the terminal block. Both terminal blocks include fastening hardware.

Terminal Block
With 120 Ohm Termination

Rugged Sealed
Terminal Block
TERMINATION GUIDE
The ISO-485-PI9 terminal block has an optional built-in 120 ohm termination. 120 ohm termination is an advanced feature typically used to reduce noise and signal reflections. It is recommended to use 120 Ohm termination if you are exceeding 600 feet in distance, 19.6K baud or in a noisy environment. The terminal blocks are shipped with 120 Ohm termination off but can be turned on using the convenient jumper setting located on the left bottom of the terminal block.

3 Position With 120 Ohm Off

3 Position With 120 Ohm On


















Using two ISO-485-PI9 units:
- Check that all connections comply with the connection diagrams.
- Perform a loop back test on two units:
-
- Connect the two RS-485 ports.
- Connect the two RS-232 ports to two PC RS-232 ports.
- Running hyper terminal programs on both PCs, send ASCII characters to the ISO-485-PI9 converter from one PC port, and check that the characters are received at the 2nd PC port. Repeat the test in the opposite direction. This tests that the transmit and receive functions of both ISO-485-PI9 units are working properly.
Download FREE FULL VERSION AccessPort Advanced Serial Monitor, Simulation and Data Analysis Software Tool. This software tool is great for testing converters. Supports Windows 98/XP/VISTA/WIN 7/WIN 8/WIN 10. DOWNLOAD SOFTWARE AND USER MANUAL
Below are some of the Opto-Isolated RS232 to RS485 converter applications.

FIGURE 1: EXTENDING THE RS232 DATA DISTANCE WITH 2500V ISOLATION
