Specifications

Operating Modes
2-15
If the transmitting DTE sends characters to the port at a slightly faster rate than the DAP
removes them, the DAP deletes stop bits from the incoming characters. If the
transmitting DTE sends characters to the port at a slower rate than they are removed, the
DAP inserts extra stop bits between characters. At the receiving end, if the DAP receives
characters at a faster rate than they are passed to the DTE, the DAP reduces the length of
a stop bit.
The maximum DTE/DAP rate differential for which the Excalibur Multirate DAP can
compensate depends on the asynchronous mode you select. In Normal mode, the DAP
can compensate for a rate differential of +1%, -2.5%. In Extended mode, the maximum
rate differential allowed is +2.3%, -2.5%. The use of Normal mode is preferred because it
results in lower distortion. The converter accepts either 8, 9, 10, or 11 bit characters with
one unit start bit and one unit stop bit. Data units can be replaced by additional stop bits.
Port speeds from 75 bps to 19.2 Kbps are supported. The minimum DAP channel rate is
2400 bps for DDS, DDS-SC, LADC, and LDM services. For DDSNI and C64NI
services, the minimum DAP channel rate is 1200 bps. If asynchronous rates below these
speeds are required, the DAP channel rate remains at 2400 bps or 1200 bps and the
asynchronous/ synchronous converter handles the rate adaption.
Note: LADC is only available for units equipped with the Model A or C Aggregate
card.