Table 3-5. Baud Rate Examples - Comtech EF Data DMD-2050E Installation And Operation Manual

DMD2050E Universal Satellite Modem
rate through the modem. The overhead channel is recovered at the far end. This added channel
is termed variously "An Overhead Channel", "Service Channel", "Async Channel" or in IESS
terminology an "ES to ES Data Channel." The basic frame structure used by the multiplexer is
that specified in the IESS-309 Standard, resulting in a 16/15 Aggregate t0 through-Data Ratio.
For Regular Async:
For Enhanced Async:
The maximum Baud Rate is 19,200 bps for IBS Async. Two software-controlled modes are
designed into the card to best utilize the available bits; "Standard IBS" and "IBS (Async)". The
characteristics of the Channel Interface is also determined by the standard or Async mode.
The Async Channel can be set under software-control to either RS-232 or RS-485 mode. The pin
assignments for both modes are shown in Table 3-5. The "RS-485" Setting controls the output
into tri-state when the modem is not transmitting data, allowing multiple modem outputs to be
connected together.
MN-DMD2050E Revision 2
(Standard IBS), the Baud Rate is approximately 1/2000 of the
Data Rate listed in Table 3-5.
(IBS Async.), the Baud Rate is selectable, but Data Rate is
limited.

Table 3-5. Baud Rate Examples

Standard IBS
Kbps
Baud Rate Example
128 64
256 128
384 192
512 256
640 320
768 384
896 448
1024 512
1152 576
1280 640
1408 704
1536 768
1664 832
1792 896
1920 960
1920 960
2048 1024
Enhanced Mode
Kbps
Baud Rate Example
9.6 300
19.2 600
32 600
64 1200
128 2400
192 4800
256 4800
320 9600
384 9600
448 9600
512 9600
576 9600
640 19200
704 19200
768 19200
768 19200
832 19200
Theory of Operation
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