The table below shows the factory default jumper settings for the 75
ohm rear card. Following the table is a description of each jumper’s
function and possible settings. When configuring the jumpers, take
care not to lose the individual straps.
LK1: Receive Shield-to-Ground Connection
This setting determines whether or not the RX shield is connected
to earth ground. This connection may help EMC performance in some
cases.
LK1
Setting
Strap On
RX Shield-to-GND Connection Made
Strap Off
RX Shield-to-GND Connection Broken
LK2: DTE Signal Ground-to-Frame Ground (with Resistor)
This setting determines whether or not the DTE signal ground
(DB-15 pin 8) is connected to frame ground (pin 1) by way of a 100
ohm resistor. This connection is recommended as a current limiter for
ground fault events.
LK2
Setting
Strap On
SGND-to-FGND Connection Made
Strap Off
SGND-to-FGND Connection Broken
4.0 INSTALLATION
This section describes the functions of the Model 1000R16 rack
chassis, tells how to install front and rear Model 2703RC cards into the
chassis, and provides diagrams for wiring the interface connections
correctly.
4.1 THE MODEL 1000R16 RACK CHASSIS
The Model 1000R16 Rack Chassis (Figure 6, below) has sixteen
device card slots, plus its own power supply. Measuring only 3.5” high,
the Model 1000R16 is designed to occupy only 2U in a 19” rack.
Sturdy front handles allow the Model 1000R16 to be extracted and
transported conveniently.
4.1.1 THE RACK POWER SUPPLY
The power supply included in the Model 1000R16 rack uses the
same mid-plane architecture as the modem cards. The front card of
the power supply slides in from the front, and the rear card slides in
from the rear. They plug into one another in the middle of the rack.
The front card is then secured by thumb screws and the rear card by
conventional metal screws.
11
12
Figure 6. Model 1000R16 Rack Chassis with power supply
WARNING!
There are no user-serviceable parts in the
power supply section of the Model 2703RC. Voltage set-
ting changes and fuse replacement should only be per-
formed by qualified service personnel. Contact Patton
Electronics Technical support at (301)975-1007 for more
information.
75 OHM REAR CARD JUMPERS
Jumper
Function
Factory Default
LK1
RX Shield to GND
Strap Off
LK2
(DTE) SGND to FGND
Strap On
