0049-0117-100 DSP9612 Flash Poll Modem – User Guide
10/12/2011
Rev. F1
Page 22 of 44
SW3-1
−
Fast Poll Auto Rate/FSK
SW3-1
ON = Low-Speed Mode (FSK)
OFF = High-Speed Mode (Fast Poll)
The modem has two operating modes:
FSK mode, which supports data rates from 0 to 1800 bps.
Fast-poll mode, which supports data rates of 4800 and 9600 bps.
SW3-1, along with the Data Rate Selector (DRS) pin on the modem’s RS-
232 connector, configures the modem for either FSK or fast-poll mode.
Table 2-6 shows how SW3-1 and the DRS signal configure the modem for
these operating modes.
Table 2-6. Modem Operating Mode
To Select… Set SW3-1
to…
And the DRS
Signal…
Fast-poll
mode
OFF
Is not connected
or is set HIGH
FSK mode
OFF
Is set LOW
FSK mode
ON
Doesn’t care
You should use the DRS signal in RTS control mode. It does not work in
either constant carrier mode (SW3-8 set to ON) or in the auto-RTS mode
(SW3-4 set to ON). The DRS signal is only sampled when the transmitter
is idle (when not sending a preamble, data, or a turn-off sequence).
Note that DRS control both the transmitter and receiver. If DRS changes
states while the modem is receiving a preamble, data, or a turn-off
sequence, the state of the receiver is unknown until the carrier drops and
a new preamble is received. We recommend that DRS do not change
states until both the local and remote modems’ transmitters are in the idle
state. When they are, both the local and remote modems’ DRS signal
should change states.
Содержание DSP9612
Страница 5: ...0049 0117 100 DSP9612 Flash Poll Modem User Guide 10 12 2011 Rev F1 Page 4 of 44 NOTES ...
Страница 9: ...0049 0117 100 DSP9612 Flash Poll Modem User Guide 10 12 2011 Rev F1 Page 8 of 44 NOTES ...
Страница 43: ...0049 0117 100 DSP9612 Flash Poll Modem User Guide 10 12 2011 Rev F1 Page 42 of 44 ...
