|5FE6 ::: QUATECH DS-1000 Dual Asynchronous RS-232|
Technical information contained in this page are edited excerpts from the QUATECH Reference Manual (ds-1000.pdf), Copyright © Quatech Inc.
|Bus interface||MicroChannel 16-bit|
|Two D-9 male connectors *|
Two D-25 male connectors *
|Transmit drivers||MC1488 or compatible|
|Receive buffers||MC1489 or compatible|
|I/O address range||16 base addresses selected through POS|
|Interrupt levels||IRQ 3, 4, 7, 9|
|500mA typical, 575mA maximum|
|38mA typical, 46mA maximum|
|36mA typical, 43mA maximum|
* Connector pinout is described in the DS-1000 Reference Manual. The optional D-25 male connectors are available using the provided adapter cables.
The DS-1000 is a dual channel RS-232C asynchronous serial communication adapter for the PS/2. The DS-1000 is designed to be used in the Serial 1 through Serial 8 address range as specified for the PS/2, although eight other addresses are available for applications requiring additional serial ports. The available interrupt selections (IRQ 3, 4, 7 and 9) can be used to reduce the number of interrupt sources on a single interrupt input. This feature can reduce software overhead in interrupt driven, high throughput applications.
The DS-1000 address and interrupt selections are selected through the Programmable Option Select (POS) using the IBM installation utilities. In addition, jumpers are provided on the DS-1000 to configure the adapter Data Terminal Equipment (DTE) or Data Communications Equipment (DCE). DTE/DCE selection can ease the cabling burden in local applications where MODEMS are not required.
The 16550 is an upgrade of the standard 16450 Asynchronous Communications Element (ACE). Designed to be compatible with the 16450, the 16550 enters the character mode on reset and in this mode will appear as a 16450 to user software. An additional mode, FIFO mode, can be selected to reduce CPU overhead at high data rates. The FIFO mode increases performance by providing two internal 16-byte FIFOs (one transmit and one receive) to buffer data and reduce the number of interrupts issued to the CPU.
Each channel of the DS-1000 uses 8 consecutive I/O address locations. The base addresses are independent but must begin on an even 8-byte boundary (xxx0H - xxx7H or xxx8H - xxxFH). The numbers xxx are controlled by the Programmable Option Select (POS) and address decoders to provide complete 16-bit addressing for each channel. Sixteen choices of base address are provided for each channel and include the eight addresses defined as SERIAL 1 through SERIAL 8. The remaining eight addresses are a constant 8000H offset from these values. A complete table of available addresses may be found in the DS-1000 Reference Manual.
RS-232-C devices are classified by their function as either Data Terminal Equipment (DTE) or Data Communication Equipment (DCE). Generally, data terminal equipment is defined as the communication source while data communication equipment is defined as devices that provide a communication channel between two DTE type devices.
Data terminal equipment and data communication equipment have complementary pinouts to allow terminals and MODEMs to be connected directly using a one-to-one cable. In many applications, DCEs are unnecessary because of the short distances involved. In these cases, a custom cable called a null MODEM or MODEM eliminator is usually required to perform the direct connection of two DTEs. To further simplify these connections, the DS-1000 is equipped with a DTE/DCE jumper configuration block for each channel. This allows the DS-1000 to communicate with DCE or DTE devices without any special cabling.
ADF Adapter Description File
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