Impulse 3440 - Manual (Page 17)

Technical Description
Sealevel Systems ULTRA COMM+422 Page 14
Technical Description
The ULTRA COMM+422 utilizes the 16550 UART. This chip features
programmable baud rates, data format, interrupt control and a 16-byte input and
output FIFO. Also available as options are the Startech 16C650 and the Texas
Instruments 16C750 UARTs, that provide deeper FIFOs (32 bytes) and
enhanced clocking features.
A second version of the ULTRA COMM+422, p/n 3441 is available without
the auto enable feature for a reduced price. If point to point RS-422 or RTS
enabled RS-485 operations are desired, this option should be considered.
Features
• Automatic RS-485 driver enable/disable allows card to appear to be RS-232
requiring no additional drivers
• ‘PAL’ option allows for unique OEM address selection
• ‘Shareable’ IRQs allow more than one port to share a single IRQ
• IRQs 2/9-7, 10, 11, 12, 15 supported
• 16550 buffered UARTs standard, 16650 and 16750 UARTS available
• 16 Bit address decode allows for easier integration
• Speeds up to 460.8 K bps available
• Multiple clocking modes insuring compatibility with existing software
products
Modem Control Signal Considerations
Some software packages require the use of the modem handshake signals such as
RTS or CTS. Refer to your application software manual to determine the
requirements for modem control signals. If no requirements are mentioned, a
safe configuration is to tie RTS to CTS. This configuration will typically satisfy
the modem control signal requirements for most communications software.