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TX
RX
DS5
-12V
GND
TP19
6
JP1
JP4
JP2
1
1
JP5
JP3
1
2
1
1
JP11
+12V
TP17 TP18
TP2
TP1
TP3
GND
TP15
TP4
TP6
TP8
TP14
TP5
GND
JP13
DS4
DS3
1
DS2
DS1
TP9
8
2
TP10
GND
TP13
TP11
TP7
TP12
JP12
+5V
TP20
TP16
TP21
JP10
JP8
1
1
2
4
2
4
JP6
1
2
4
-5V
GND
JP9
JP7
P1
F1
SW1
J4
J1
FIGURE 3. F22XX MODEM JUMPER AND TEST POINT LOCATIONS
2.4.2 Jumpers for Input Impedance Selection
Channel 1 (Transmit Data) and Channel 2 (Synchronous Transmit Clock or Asynchronous
Data #2) will be set for high impedance when jumpers JP7 and JP9 are not inserted. If JP7 and
JP9 are present, the input impedance is 100 ohm. The 100 ohm termination is not available on
the DTR input.
2.4.3 Jumpers for Transmit Clock Selection
The transmitter operating mode is controlled by jumper JP1. For automatic, rate-dependent
selection of transmitted synchronous clock and data, set JP1 = 3-4. To have the input data
stream synchronized to the internal 10 MHz clock while being processed ("forced sync"), set JP1
= 1-2. For fixed over-sampling of asynchronous data ("forced async"), set JP1 = 5-6. On the
circuit board, pins 1, 3, and 5 are tied together, so the jumper appears as follows:
1o 3o 5o
2o 4o 6o
2.4.4 Jumpers for Receive Clock Selection
For automatic mode (receiver tracking transmitter, full duplex operation) receive clock and
data, set JP3 = 2-3 and JP13 = 1-2, 7-8. For forced synchronous mode (data clocked by internal
10 MHz clock), set JP3 = 2-3 and JP13 = 5-6, 7-8. For forced asynchronous mode, if the
receiver is being used with no transmit clock, or for two asynchronous data channels, set JP3 =
1-2 and JP13 = 1-2, 7-8.
LOOP
Model
F2238
PWR
VERSITRON
TX
RX
LB
OFF
ON
LB
