These are eight or four-port, asynchronous, serial communication boards designed for use on the PC/104 bus. They support RS-485 and RS-422 communications. The boards may be installed in any standard PC/104 stack. Connections are made via a 50 pin IDC type right angle connector.
Common applications include POS, gaming systems, machine monitoring, military and highdensity networking.
Type 16550 UARTS are used as the asynchronous communication elements. These include 16-byte transmit/receive FIFO buffers to protect against lost data in multitasking systems while maintaining 100% compatibility with the original IBM serial port.
A crystal oscillator located on the board permits precise baud rate capability up to 115,200. Higher speeds, up to 921.6K, are achieved by installing a jumper on the board. The driver/receivers used, type SN75176, are capable of driving long communication lines at high baud rates. They can drive up to ±60 mA on balanced lines and receive inputs as low as 200 mV differential signal superimposed on common mode noise of 12 to -7V. In case of communication conflict, the driver/receivers feature thermal shutdown.
This board may be operated in two modes. In the Default Mode, the base address for the board is selected by jumpers and all of the channel addresses are sequential. Because it is sometimes difficult to find a large enough block of addresses to permit this approach, an alternative is provided. The addresses and interrupts of the individual channels may be stored in non volatile memory on the board and loaded into programmed logic when the board is initially powered. Individual interrupts for each channel are programmed into the non-volatile memory in both modes.
AUTO TRANSCEIVER CONTROL
In RS-485 multidrop communications individual drivers must be enabled when needed and then disabled after use to permit all ports on the network to share a two-wire or four -wire cable. The 104-COM-8S (and 104-COM-4S) uses an automatic (AUTO) control. The driver is enabled (and the receiver disabled) when data is ready to be transmitted. When transmission is complete, the driver remains enabled for the transmission time of one additional character and then is disabled. This is ideal for use in Windows based applications.
UTILITY SOFTWARE
The 104-COM-8S Series is supported by all operating systems and include a free DOS, Linux and Windows 95/98/Me/NT/2000/XP/2003 compatible software package. This includes sample programs and source code in "C" and Pascal for DOS, and Visual Basic, Delphi, C Builder, and Visual C for Windows. Also included is a graphical setup program in Windows. An easy-to-use Windows terminal program simplifies verification of proper operation.
Specifications
Communications Interface
- I/O Connections: Via a 50 pin IDC type right angle connector. There are four pins per port plus common grounds.
- Character Length: 5,6,7, or 8 bits
- Parity: Even, odd, or none
- Stop Interval: 1, 1.5, or 2 bits
- Serial Data Rates: Up to 115.2K baud, asynchronous. A faster range of rates, up to 921.6K, is achieved by jumper selection.
- Multidrop: Compatible with RS-485 specifications. Up to 32 drivers and receivers allowed on line. Driver/Receivers used are type 75ALS180.
- Compatible with RS-422 specifications. Up to ten receivers allowed on line.
- Address: ISA BUS address is set by jumpers on the board. A “Default” jumper determines whether the channel addresses are sequential or loaded from nonvolatile memory on the board.
- Interrupts: Individual IRQs for each channel are stored onboard in non-volatile memory.
- Receiver Input Sensitivity: ±200 mV differential input
- Common Mode Voltage Range: 12V to -7V
- Transmitter Output Drive Capability: 60 mA with thermal shutdown. Jumper selectable terminations for input and output, by channel, are provided.
Environmental
- Operating Temperature: 0 to 70°C, (-40 to 85°C Optional)
- Storage Temperature Range: -50 to 120°C
- Humidity: 5% to 95% RH, non-condensing
- Power Required: 5 VDC at 80 mA typical, all outputs open
CE testing & approval must be done at the system level, in the designed enclosure, and is not done on individual boards.
