Black Box MicroRACK RM208, Manual

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CHAPTER 4: Configuration
Character Length
Choosing option 4 in the Software Switch Menu takes you to the Character Length
Menu. In asynchronous data format, the Card supports 10-bit and 11-bit character
lengths. Set this option according to the characteristics of the data being
transmitted.
CHARACTER LENGTH MENU—Esc to exit
1. 10 Bit Character Length (DEFAULT)
2. 11 Bit Character Length
Figure 10. Character Length Menu.
DTE Data Format
Choosing option 5 in the Software Switch Menu takes you to the Data Format
Menu. This option controls whether an async-to-sync conversion is performed
between the DTE and the Card. (Data is always transferred synchronously between
two Cards.) For an asynchronous DTE, select the asynchronous data format. For a
synchronous DTE, select the synchronous data format.
DATA FORMAT MENU—Esc to exit
1. Asynchronous Data Format
2. Synchronous Data Format (DEFAULT)
Figure 11. Data Format Menu.
NOTE
The async rate of 57.6 Kbps is supported at the 56 Kbps line rate,
provided the DTE equipment is configured to transmit two stop bits. The
extra stop bit reduces the DTE’s effective data rate to allow
synchronization with the 56 Kbps line speed. Set the Card for two stop
bits by selecting “11 bit character length” in the Character Length Menu.
NOTE
You can use the Card to transmit lower-speed asynchronous data (up to
9.6 Kbps) over synchronous circuits by simple over-sampling. To do
this, select the synchronous data format and set the line Line Rate
(Software Switch Menu option 1) to at least four times that
asynchronous data rate you wish to send. For example, use a Line Rate
of 9.6 Kbps or higher for 2.4 Kbps async data.