ADLINK cPCI-3534/3538/3544 Multi Serial Port Card Configuration Complete Solution



ADLINK cPCI-3534/3538/3544 Multi Port Serial Communication Module Complete Guide

In the fields of industrial automation, data acquisition, and telecommunications equipment, multi port serial communication remains an important way to connect various terminal devices such as modems, data acquisition terminals, and display devices. The CompactPCI (cPCI) platform is widely used in key industries such as transportation, power, and military due to its robust mechanical structure, hot swappable capability, and high reliability. ADLINK cPCI-3534 (4-port, 3xRS-232+1x isolated RS-422/485), cPCI-3544 (4-port fully isolated RS-422/485), and cPCI-3538 (8-port RS-232) serial communication modules are mature solutions that provide high-density and high reliability serial port expansion for these occasions. This article is based on the original user manual and provides a comprehensive technical archive and operation guide for engineers who are still maintaining or creating cPCI serial port systems, covering hardware architecture, pin definitions, jumper configuration, multi card recognition, and multi operating system driver installation.

Product Series Overview and Selection Differences

cPCI-3534、 Both 3538 and 3544 adopt 3U cPCI specifications (160 × 100mm), 32-bit PCI Rev.2.1 bus, support plug and play (IRQ and I/O addresses are automatically allocated by PCI BIOS), and the core serial controller is 16C550A compatible (clock 1.8432~7.3728MHz), with a maximum speed of 115200bps per port. Both are equipped with intelligent buffers (FIFO) to reduce CPU load.

Model Port Configuration Interface Type Isolation Characteristics Maximum Port/System Special Features

CPCI-3534 4-port (A/B/C is RS-232, D is RS-422/485) DIP switch selection only Port D isolation (2500VDC) 8-port (2 cards) supports mixed interfaces

CPCI-3544 4-port full RS-422/485 DIP switch selection, inter channel isolation (500VDC), 32 ports (8 cards), RS-485 automatic direction control

CPCI-3538 8-port full RS-232 pure RS-232 without onboard isolation (optional external C888XB) 16 port (2 cards) high-density standard serial port

Key selection points:

If the on-site equipment mainly consists of standard RS-232 devices (such as old-fashioned modems, industrial computer debugging ports) and requires 8 high-density channels, cPCI-3538 should be selected.

If a small amount of RS-232 is required to be paired with one isolated RS-422/485 (such as connecting remote smart meters), choose cPCI-3534.

If all on-site equipment is RS-422/485 (such as multiple frequency converters, PLCs), and it is required that channels be isolated from each other to avoid ground loop interference, cPCI-3544 should be selected.

If the chassis supports Rear I/O, choose a model with an "R" suffix (such as cPCI-3534R), and use the cPCI-R3534/R3538/R3544 rear board to achieve Rear I/O.

Detailed explanation of hardware interfaces and pin definitions

1. cPCI-3534 (DB37 female head, with 4 ports)

The front panel of the module is equipped with a DB37 female connector, which can be connected to four ports through the accompanying branch cables (C425M with DB25 male connector, or C409M with DB9 male connector).

RS-232 ports (A, B, C) standard signals: TXD, RXD, RTS, CTS, DSR, DTR, DCD, RI, GND, complete 9-wire system, supporting hardware flow control.

Port D (isolated RS-422/485) pin mapping (using DB25 as an example):

Pin 2: TXD+(422) or unused (485)

Pin 3: RXD+(422) or unused (485)

Pin 4: RTS (422) or D+(485)

Pin 5: CTS (422) or D - (485)

Pin 6: RXD - (422 input negative terminal) or unused (485)

Pin 7: Isolated GND

Pin 20: TXD - (422 output negative terminal) or unused (485)

Switching method: Select Port D as RS-422 or RS-485 through the onboard SW1-4 dip switch. At the same time, JP1 (RS-422 terminal resistor) and JP2 (RS-485 terminal resistor) can be enabled with 120 Ω terminal matching through jumper caps, and must be enabled as needed for long-distance communication.

2. cPCI-3544 (DB37 female head, 4-port fully isolated RS-422/485)

Pin allocation is similar to 3534, but all ports are differential signals and each port has an independent isolated ground (rather than shared). Taking DB25 as an example:

Pin 2: TXD+

Pin 3: RXD+

Pin 5: D+(RS-485)

Pin 6: RXD-

Pin 7: This port is isolated from the ground

Pin 8: D - (RS-485)

Pin 20: TXD-

Terminal resistance: Each port corresponds to two sets of jumpers - JP1/JP3/JP5/JP7 for RS-422 terminals, JP2/JP4/JP6/JP8 for RS-485 terminals. Key: The installation of jumper caps enables terminal resistors, which need to be determined based on the length of the cable and the number of nodes.

Multi card recognition: Set the card number (0-7) through the SW1-3 dip switch, supporting up to 8 cards (32 ports), and the card number must be unique.

3. cPCI-3538 (DB62 female, 8-port RS-232)

DB62 leads out 8 channels of full signal RS-232 (TXD, RXD, RTS, CTS, DSR, DTR, DCD, GND), which are connected to external devices through C825M (DB25 branch) or C809M (DB9 branch) cables. Pin allocation is arranged in the order of ports A to H (see Table 1-5 in the manual for details), for example:

Port A: Pin 1=TXD, 2=RXD, 3=RTS, 4=CTS, 5=DSR, 6=DTR, 7=DCD

Ports E~H and so on, pins 43~62 are GND.

Multi card recognition: Set the first card (ON) or second card (OFF) through JP1 jumper, supporting up to 2 cards (16 ports).

Hardware configuration and coexistence of multiple cards

1. Card number setting

CPCI-3534/3538: Setting SW1-1 (3534) or JP1 (3538) to ON indicates that the card is the "first card" in the system, and OFF indicates the "second card". Due to the cPCI bus supporting up to 2 cards of the same type, the first card is assigned a lower COM port number (such as COM3-6), and the second card is assigned a higher port number (such as COM7-10). It is strictly prohibited to set both cards to ON or OFF at the same time, otherwise the system cannot distinguish and may cause resource conflicts.

CPCI-3544: Set the card number through SW1-3 three digit dialing (binary 0-7), supporting up to 8 cards. The card number determines the enumeration order of ports in the system, especially when multiple cards coexist, a unique card number must be assigned to each card.

2. Terminal resistor configuration

RS-422: When communicating point-to-point, only the terminal resistor needs to be enabled at the receiving end (i.e. module side). If the module serves as the receiving end, the RS-422 jumper of the corresponding port should be turned on.

RS-485: Multi point half duplex bus, one terminal resistor must be enabled at each of the two farthest ends of the physical circuit. If the module is located at the end of the bus, the corresponding RS-485 jumper is ON; if it is located at the middle node, it is OFF.

Incorrect configuration of terminal resistors can cause signal reflection (increased bit error rate) or driver overload (waveform distortion). When debugging, the jumper status should be checked first.

3. Isolation and grounding

The Port D of cPCI-3534 is an isolated port (2500VDC), and its isolated ground (GND) is independent of the system digital ground (GND). When wiring, it cannot be mixed, otherwise the isolation effect will be damaged.

Each port of cPCI-3544 is independently isolated (500VDC), and the ports are isolated from each other and from the system ground, making it particularly suitable for connecting devices distributed in different potential areas.

Full process of installing multiple operating system drivers

1. Windows NT 4.0 (Classic Industrial System)

Log in as an administrator, open Control Panel → Network → Add Adapter.

Select 'Install from disk' and specify the drive path (corresponding directory in CD-ROM):

3534/3538: X:  NuCOM  CCPI3534  NT4 (or 3538)

3544：X:NuCOMCPCI3544NT4

During the installation process, specify the starting COM port number (starting from COM3 by default to avoid conflicts with onboard COM1/2).

Multi card rule: The first card (SW1-1=ON or JP1=ON) receives a lower COM number, and the second card (OFF) receives a higher COM number. If multiple cards are installed simultaneously, ensure that the switch status of each card is mutually exclusive.

After restarting, the system adds a new COM port, which can be verified in the Device Manager.

2. Windows 95/98 (plug and play)

After the system starts, it automatically detects new hardware and follows the prompts to specify the driver path. Due to the dynamic allocation of resources by PCI BIOS, multi card recognition relies entirely on the ON/OFF status of SW1-1/JP1 to determine which card is the first (low COM number) and which is the second (high COM number). If two cards have the same status, the system may not be able to allocate resources correctly, resulting in some ports being unavailable.

3. Windows 2000/XP (stable compatibility)

After plug and play detects a new card, specify the driver location through the "Add New Hardware Wizard":

3534/3538：X:SerialCommcPCI-353XWin2000-XP

3544：X:SerialCommcPCI-3544W2000

Similarly, 3534/3538 distinguishes the first/second card through JP1/SW1-1; 3544 uses the SW1-3 card number to determine the enumeration order. This mechanism ensures that even if the PCI slot is replaced, the COM port number remains fixed, which is crucial for industrial applications.

4. Linux (applicable to 3534/3538 and 3544 respectively)

3534/3538：

Extract alnxsrc. Z (located on CD X:  SerilComm  cPCI-353X  Linux), create a floppy disk image using dd, and tar it to/etc/rayon.

Execution /Install， Select the target card type according to the prompt.

Note: The system needs to have kernel source code (/var/src/Linux), otherwise compilation may fail.

3544：

Extract pci3544.tgz to obtain the cPCI_3544 directory.

Execute the installation script 3544_inst.l-cards N (where N is the actual number of cards), specifying the TTY master device number and Callout master device number (default 70/71).

The script automatically detects the 3544 devices on the cPCI bus and creates corresponding nodes (/dev/ttySx and/dev/cuix), and then can use open/read/write operations like a regular serial port.

Wiring examples and debugging points

1. RS-232 standard wiring (3534 A/B/C or 3538 all)

Connect to the terminal device using C425M (DB25) or C409M (DB9) cables. Note:

If the device is DCE (such as a modem), use a direct line; If it is a DTE (such as a computer), a crossover cable (TXD) is required ↔ RXD，RTS ↔ CTS，DTR ↔ DSR，DCD ↔ RI depending on the situation.

It is recommended to only connect the necessary signal lines (TXD, RXD, GND). If hardware flow control is required, connect RTS/CTS.

2. RS-422 full duplex wiring (3534 Port D/3544)

The TXD+/- of the module is connected to the RXD+/- of the slave device, and the RXD+/- of the module is connected to the TXD+/- of the slave device. Shielding layer single ended module side isolation ground. Enabling terminal resistors (module side jumper ON) can improve the quality of long line signals (up to approximately 1200 meters).

3. RS-485 half duplex wiring (3534 Port D/3544)

Connect all devices' D+to D+and D - to D - to form a bus topology. Only enable terminal resistors for devices at both ends of the bus. CPCI-3544 supports automatic direction control (hardware automatically switches between transmitting and receiving states), without the need for software control of RTS, simplifying programming; The Port D of 3534 needs to be set to 485 mode through DIP switch and controlled by RTS signal direction (or use automatic flow control mode, depending on specific driving support).

Common troubleshooting guide

Possible causes and solutions for the fault phenomenon

The system cannot recognize poor contact in the PCI slot of the card or incomplete insertion and unplugging of the card. Check the power supply of the cPCI chassis backplane

COM port number conflict, multiple card switch status settings are the same. Check SW1-1/JP1 of 3534/3538 to ensure one is ON and one is OFF; 3544 Check if the card number is unique

Serial communication garbled baud rate/data bit/stop bit mismatch; Or if the terminal resistor configuration is incorrect, check the parameters at both ends; Check the RS-422/485 terminal jumper

RS-485 can only send but cannot receive. Direction control is not effective (RTS control is required for 3534, automatic for 3544). Check if the software correctly pulls RTS high/low; 3544 Check if the driver is loaded with the automatic flow control module

The isolation port has no output, the isolation power supply has not been established, or the isolation ground has not been connected. Confirm that the external device is grounded together with the isolation ground; Check that the module power supply 5V is normal

Insufficient blue screen IRQ resources or driver conflict check system idle IRQ after multi card installation; Attempt to allocate independent IRQ in BIOS; Update driver version