CANOGA PERKINS 2240 Fiber Optic Modem - Manual (Page 47)

Chapter 4 Data Interfaces
RS-530 Interface Model 430
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4.3.3 CS_GATE Jumper
The CS_GATE jumper controls the state of CS when the local RS is ON. When the jumper is in
the ON position, CTS follows RS only. The CD position allows the 2240's standard data interface
signal CD to gate CS. In the CD jumper position and with local RS ON, CS will turn ON either
when the modem's fiber optic receiver is in sync (main PCBA internal switch S1 CD/DCD = OFF
and CD/SYNC = ON) or the RTS signal at the far end is ON (main PCBA internal switch S1 CD/
DCD = ON and CD/SYNC = OFF). Refer to section 2.1.3.1 for more information on the internal
switch S1 CD/DCD and CD/SYNC positions.
Factory setting: ON
4.3.4 DM Jumper
The DM jumper controls the behavior of the DM signal. The EIA position turns DM OFF when the
far-end 2240 modem has a local loopback active. The TEST position causes DM to turn OFF
whenever any loopback is active at one or both modems.
Factory setting: EIA
4.3.5 CH_GND Jumper
The jumper selects whether chassis ground is connected directly to signal ground (SHORT
position) or through a 100 Ohm resistor (100_OHM position).
NOTE: In the standalone model, the 100_OHM position will only put a 100 Ohm
resistor between the two grounds if the 2240's main board SIGNAL GND
jumper is set to the FLOAT position. When installed in the 2201 Rack
Chassis, any modem main board, interface or rack chassis jumper being
set to SHORT will override the FLOAT and 100_OHM positions on all of
the other modems. CONSIDER THIS JUMPER CAREFULLY.
Factory setting: 100_OHM
4.3.6 UNBAL_REF Jumper
RS-449 specifies that unbalanced inputs to a DCE are to be referenced to the SC (Send
Common) pin. This pin on the DCE is tied to the signal ground of the DTE through the interface
cable. If this ground connection is present, and you prefer to use it, move the UNBAL_REF
jumpers to SC.
Factory setting: GND
4.4 RS-530 Interface Model 430
NOTE: The -430 interface supersedes the previous -R30 interface for 2240
applications. The -430 interface is a superset of the -R30. If exact
compatibility with the older -R30 is desired, the DCD jumper can be
moved from the factory strapped CTRL setting (end-to-end RTS-DCD
control lead pair always enabled) to CD (DCD function selected by main
board CD/DCD and CD/SYNC switches).
This interface conforms to EIA RS-530. The interface uses RS-422 (balanced) electrical signals
for all interface circuits (data, clock and control), except for the loopback and test mode pins