Character Format; Handshake Lines; Self-Test - Black Box 202T User Manual

MODEM 202T

5.3 Character Format

To find the character format of your equipment, take the number of data bits in a
character. If parity is used (odd, even, mark, space), add one (1). If parity is not
used, don't add anything. Add two for one start bit and one stop bit. The result
must be 10 or 11. Use SW2-3 to set the length. SW2-3 is OFF for 10 bits, and ON for
11 bits. This switch is ignored in simplex mode.

5.4 Handshake Lines

If RTS handshaking mode is set, the Modem 202T needs the RTS asserted when it
is time to transmit data onto the FSK carrier from the equipment. Depending
upon how the modem is configured, it can provide DCD, CTS, and DSR signaling
back to your equipment. JP3 is used to configure these lines.
If these lines are needed, note that:
• Shorting pins 1 and 2 will pull DCD (pin 1) logic high at the DB9 connector.
• Shorting pins 2 and 3 will pass carrier status to DCD (pin 1) at the DB9
connector.
• Shorting pins 4 and 5 will route incoming RTS (pin 7) to outgoing CTS (pin
8) and outgoing DSR (pin 6) at the DB9 connector.
• Shorting pins 5 and 6 will route DSR and CTS to pin 1. Also, shorting pins 2
and 3 will connect DCD (pin 1) to outgoing CTS (pin 8) and outgoing DSR
(pin 6) at the DB9 connector.
DSR (pin 6) and CTS (pin 8) are always connected to DTR.

5.5 Self-Test

The Modem 202T has a built-in test mode that verifies whether the processor is
operating normally. It displays the operating configuration as set by the SW2
switches and the 2-/4-wire mode switch SW3.
To conduct the self-test:
1. Remove DC power.
2. Remove the cover.
18
NOTE