CANOGA PERKINS 2240 Fiber Optic Modem - Manual (Page 80)

80
Canoga Perkins
Table 4-R.
Strap
Configurations
for RLSD (CD)
Output
The W1 / W2 strap connects chassis ground to signal ground (W2 position), connects chassis
ground through 100 ohms to signal ground (W1 position), or isolates chassis ground from signal
ground (jumper out). The W5, W6 and W7 jumpers, when installed, ground the midpoints of the
100 ohm termination resistances of the FIFO CLK, SCTE and TxD line receivers. These
jumpers may provide improved performance in cases where the RS-422 inputs are bipolar rather
than the more common unipolar types. The W8, W9 and W15 / W16 jumpers are used for
converting to the Legacy configuration (see Figure 4-15).
To support Flow Control, set the CD options at the Internal Option Switches on the main 2240
board. Set SW1-1, CD/DCD to ON. Set SW1-2, CD/SYNC, to OFF. For details about the
switch, see Section 2.2.2 on page 23.
4.9.1 Jumper and Switch Settings
All jumper settings and descriptions are listed in Table 4-Q. This interface has strap option
jumpers to configure the RLSD Output at J1-8 (DB-25) to support the KG-194 Resync
functionality. Jumper straps W10 / W11 (adjacent to U11) and W12 / W13 / W14 (adjacent to
U8) implement this function (refer to Table 4-Q and Figure 4-6). Jumper straps W10 / W11
control the ON / OFF level and W12 / W13 / W14 configure the RLSD Output to Bipolar (+6 V
and -6 V) or single-ended (+6 and 0 or -6 and 0).
Table 4-Q.
Jumper Settings
and Descriptions
STRAP CONFIGURATIONS CD OUTPUT (AT J1-8 * * )
VOLTAGE LEVEL ±1 V
ON/OFF
W11 and W14 +6/-6
W11 and W12 +6/0
W11 and W13 0/-6
W10 and W14 -6/+6
W10 and W12 0/+6
W10 and W13 -6/0
* * J1-6 when using the "Legacy" (P2) Converter
Jumper Description Notes Factory
Setting
W1 / W2 Chassis Ground W1 - 100 ohms / W2 - Short W1 Default
W5, W6, W7 RCVR Terminations All Out
W8 / W9 Legacy Config. Both Out
W10 / W11 RLSD Output Swing W11
W12 / W13 / W14 RLSD Output Swing W13
W15 / W16 DSR W15 - Test / W16 - GND W16 Default
W17 / W18 RTS Bias W17 - On / W18 - Off W18 Default
W19 / W20 RLSD W19 - Single Ended / W20 Default
W20 - Differential