4 Channel Isolated Serial Interface RS422/RS485

  • Standard single-width 32 bit PMC module
  • 4 channels RS422 / RS485-HD / RS485-FD interfaces
  • Channels are isolated against system and each other
  • High performance asynchronous serial interface (up to 460.8 Kbps)
  • 128 byte FIFO
  • Front panel I/O (DB25 connector) and P14 I/O

Product status: Active

Operating Temperature Range -40 °C to +85 °C RoHS compliant

The TPMC861 is a standard single-width 32 bit PMC module with four channels of high performance RS422/485-HD/FD asynchronous serial interface. Each of the four channels is isolated from the system and against each other by optocoupler and on board DC/DC converter per channel.

The serial channels are accessible through a DB25 connector mounted in the front panel and via P14 I/O. Each channel has a 128 byte transmit FIFO and a 128 byte receive FIFO to significantly reduce the overhead required to provide data to and get data from the transmitter and receivers. The FIFO trigger levels are programmable. For RS422 and RS485-FD a four wire interface (RX+, RX-, TX+, TX-) plus isolated ground (GND) per channel is supported. For RS485-HD a two wire interface (DX+, DX-) plus isolated ground (GND) per channel is supported. The baud rate is individually programmable up to 460.8 Kbaud for each channel. Interrupts are supported.

All channels generate interrupts on PCI interrupt INTA. For fast interrupt source detection the TPMC861 provides a special interrupt status register. Each receiver input and transmitter output of all channels is protected against electrostatic discharge (ESD) up to +/- 15kV according to IEC 1000-4-2.

Software Support (TPMC861-SW-xx) is available for different operating systems.


Mechanical Interface PCI Mezzanine Card (PMC) Interface, Single Size
Electrical Interface PCI Rev. 3.0 compatible, 33 MHz, 32 bit PCI, 3.3 V and 5 V Signaling Voltage
PCI Target Chip TEWS PCI Interface FPGA
UART Controller XR16C864 (4 channel UART, RS422/485)
Number of UART Channels 4
FIFO 128 byte transmit FIFO, 128 byte receive FIFO per channel
Interrupts PCI INTA for all channels, on board interrupt status register
I/O Signals / Channel TX+/-, RX+/-, isolated GND
Maximum Transfer Rate Each channel programmable up to 460.8 kbaud
ESD-Protection +/-15 kV Human Body Model, +/-6 kV IEC1000-4-2 Model
I/O Interface DB25 female connector, 64 pins Mezzanine P14 I/O connector
Power Requirements 545 mA typical @ +5V (RS485)
Temperature Range Operating: -40°C to +85°C
Storage: -55°C to +125°C
Weight 78 g
Humidity 5-95 % non-condensing
MTBF 423797 h



4 Channel Isolated Serial Interface RS422/RS485

4 RS422/RS485 serial interfaces; isolated by optocoupler; RS485 half-duplex support; baudrates up to 460.8 kbps; Front I/O via DB25 connector; Rear I/O


DB25 M/M Cable

DB25 Terminal Block

Cable Kit for Modules with DB25 Female Connector

PIM I/O Module with 50 pin Connector


Device Driver for Multiple Channel Serial Interface Boards

Data Sheet

Data Sheet

Data Sheet - Issue 2.0.0

User Manual

User Manual - Issue 2.0.0