EKF - Short Profile
EKF - Short Profile


CompactPCI® • Quad Isolated RS-485 Interface

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Product Information
Block Diagram
RS-485 Configuration
RS-485 Alternate

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CompactPCI® Classic  •  Quad Isolated RS-485 Interface

Proven and reliable, RS-485 (EIA/TIA-485) stays a popular fieldbus communication interface, due to simple installation via low cost twisted pair copper cables, up to 1200m length.

The CUD-TWIST is a peripheral slot card for CompactPCI® systems, equipped with four isolated front panel RS-485 ports. High speed RS-485 balanced line transceivers with internal 5kV isolation barrier provide for optimum noise and EMC immunity.

The CUD-TWIST is equipped with an octal PCI Express® to UART bridge. The 950-style UARTs are compatible with many asynchronous serial applications and protocols. Four isolated EIA/TIA-485 transceivers are wired to RJ45 front panel jacks, individually configurable for full-duplex operation (4+1 wire cable) or half-duplex (2+1 wire cable), either point-to-point or multipoint applications. Another four UART channels are wired to the CompactPCI® backplane connector J2 for rear I/O usage.


CUD-TWIST • Front Panel & Rear I/O
Summary of Features

  • PICMG® CompactPCI® Classic (CPCI 2.0) standard
  • Single size Eurocard 3U 4HP 100x160mm2
  • Suitable for CompactPCI® peripheral slot
  • CompactPCI® backplane connector J1 for PCI® 32-bit 33/66MHz support
  • Option CompactPCI® backplane connector J2 for rear I/O (4 x UART TTL level signals)
  • On-board PCI® to PCI Express® bridge
  • Option +5V only power supply

  • Pericom® PCI Express® quad UART PI7C9X7958
  • High performance 950-class UARTs
  • 16C550 software compatible
  • 128-Byte FIFO for each transmitter/receiver
  • Baud rate up to 15Mbps
  • XON/XOFF in-band flow control
  • CTS/RTS or DSR/DTR out-of-band control & driver enable signal for PartyLine operation
  • Data frame 5, 6, 7, 8 and 9 bits
  • Clock prescaling 4 to 46
  • Windows® & Linux device driver support

RS-485 Transceivers
  • 5kV rms isolation barrier RS-485/RS-422 transceivers (Analog Devices)
  • Configurable as half- or full-duplex
  • ±15 kV ESD protection on RS-485 input/output pins
  • Transceiver data rate 16Mbps max.
  • Connect up to 256 nodes on one PartyLine bus (driver enable control via dedicated UART mode select outputs)
  • Open- and short-circuit, fail-safe receiver inputs
  • High common-mode transient immunity >25 kV/µs
  • Thermal shutdown protection
  • 4 x front panel RJ45 connectors 8-lead, three different pin assignments available for order:
    • RJ45 CUD-TWIST native pin order, optimized for full-duplex via Ethernet cross-over patch cables
    • RJ45 CU4-SOPRANO legacy pin arrangement for seamless changeover of applications
    • RJ45 Half-duplex operation optimized via straight Ethernet patch cable
  • RS-485 front ports isolated against each other and board circuitry
  • On-board DIP-switches for full/half-duplex setting, and line termination on/off
  • Ordering option D-Sub 9-pin front panel connectors (4 ports require 8HP F/P)

Environment, Regulatory
  • Designed & manufactured in Germany
  • Certified quality management according to ISO 9001
  • Long term availability
  • Rugged solution (coating/sealing available on request)
  • Custom specific modifications on request
  • RoHS compliant
  • Operation temperature -40°C to +85°C (industrial temperature range)
  • Storage temperature -40°C to +85°C, max. gradient 5°C/min
  • Humidity 5% ... 95% RH non condensing
  • Altitude -300m ... +3000m
  • Shock 15g 0.33ms, 6g 6ms
  • Vibration 1g 5-2000Hz
  • MTBF 34.7 years
  • EC Regulations EN55022, EN55024, EN60950-1 (UL60950-1/IEC60950-1)

CUD-TWIST Simplified Block Diagram

CUD-TWIST Simplified Block Diagram


CUD-TWIST • Option D-Sub Connectors

The CUD-TWIST is equipped with the Pericom PI7C9X7958 PCI Express® octal UART, which is suitable for asynchronous baud rates up to 15Mbps. Four UART channels are wired to RJ45 front panel jacks across RS-485 transceivers. According to the RS-485 transmission line standard, only the UART receive and transmit data signals are in use, and in addition mode output pins which act as RS-485 driver and receiver enable control, as required for half-duplex multipoint configurations.

Four ADM2682E transceivers are provided to meet the RS-485 physical layer specifications. The RS-485 signals of any particular RJ45 front panel jack are isolated from the board circuitry, and also isolated from each other port. As manufacturing option, three different pin assignments are available for the RJ45 jacks, a CUD-TWIST native alignment which would allow low-cost Ethernet patch cable use for RS-485, and a legacy CU4-SOPRANO layout, and in addition a half-duplex optimized variant.

As an alternate to the RJ45 jacks, four 2.54mm pitch pin headers PU1-4 can be optionally populated on-board, for attachment of classic D-Sub 9-pin connectors by means of micro ribbon flat cables, to be combined with a non-standard 8HP width front panel. Three different DB9 pin assignments are available as manufacturing option.

The CUD-TWIST can be configured also for rear I/O usage. Four UART ports are wired as TTL level signals to the optional backplane connector J2, for use with a suitable RIO PHY module, typically configured as either RS-232 or RS-485. Hence, with both front and rear I/O capabilities utilised, the CUD-TWIST is a true 8-port asynchronous serial interface solution.

As an alternate to J2 RIO, optional 2.0mm pitch shrouded headers PU5-8 can be provided for attachment of CU-series PHY modules.

CUD-TWIST RS-485 Termination Options (RJ45 Native Pin Assignment)

CUD-TWIST RS-485 Termination Options (RJ45 Native Pin Assignment)

CUD-TWIST RS-485 Termination Options (RJ45 CU4-SOPRANO Legacy Pin Assignment)

CUD-TWIST RS-485 Termination Options (RJ45 CU4-SOPRANO Legacy Pin Assignment)
Ordering Information
Please refer to List 20 for popular SKU
EKF is an ISO-9001 certified company
EKF Elektronik GmbH • Philipp-Reis-Str. 4 • 59065 Hamm • Germany
Phone +49 (0)2381/6890-0 • Fax +49 (0)2381/6890-90 • E-Mail