3.4 CONFIGURATION SWITCH SET “S3”
The DIP switches on S3 set the anti-stream control, local loopback
enable, remote loopback enable and receive (input) impedance levels
for the Model 1080A Series. Factory default positions of Switch S3 are
shown in the table below.
Switches S3-1 & S3-2: Input Impedance
The setting for Switches S3-1 and S3-2 determines the 1080A
Series’ input impedance. This allows you to choose the optimum
impedance setting for your application. In long distance applications
the impedance of the cable must match the impedance of the load (or
resistor) of the Model 1080A Series unit. Thicker gauge cables
requires a lower Ohm setting, while a thinner gauge cable should
receive a higher Ohm setting. If you are using higher speeds you will
need a lower Ohm setting, and a higher Ohm setting for the slower
speeds. Refer to the table on the following page for assistance in
selecting a setting.
S3-1
S3-2
Setting
On
On
130 Ohms
On
Off
200 Ohms
Off
On
320 Ohms
Off
Off
High impedance (minimum 2k
Ω
)
9
S3 SUMMARY TABLE
Position
Function
Factory Default
S3-1
Input Impedance
On
S3-2
Input Impedance
Off
S3-3
Not yet assigned
n/a
S3-4
Mode Selection
On Point to Point
S3-5
Local Loopback
Off
Disabled
S3-6
Remote Loopback
Off
Disabled
S3-7
Anti-stream Control
Off
S3-8
Anti-stream Control
Off
200 Ohms
Disabled
}
}
Switch S3-4: Mode Selection
The setting for switch S3-4 allows the user to choose the
appropriate setting for point-to-point or multipoint applications.
S3-4
Setting
On
Point-to-point
On
Multipoint application as “Master”
Off
Multipoint application as “Slave”
Switch S3-5: RS-232 Initiation of Local Loopback Test
The setting for switch S3-5 determines whether or not the Model
1080A Series’ local analog loopback test can be initiated by raising pin
18 on the RS-232 interface.
S3-5
Setting
On
RS-232 initiation enabled
Off
RS-232 initiation disabled
10
S3-1, S3-2 SELECTION TABLE FOR MODEL 1080A
Gauge of
Cable
19AWG/.9mm
22AWG/.6mm
24AWG/.5mm
26AWG/.4mm
1.2
320
320
320
320
Data Rates, kb/s
1.8
320
320
320
320
2.4
200
320
320
320
3.6
200
200
320
320
4.8
200
200
200
320
7.2
200
200
200
200
9.6
200
200
200
200
14.4
130
200
200
200
19.2
130
130
200
200
28.8
130
130
130
200
38.4
130
130
130
130
57.6
130
130
130
130
S3-1, S3-2 SELECTION TABLE FOR MODEL 1080A-64
Gauge of
Cable
19AWG/.9mm
22AWG/.6mm
24AWG/.5mm
26AWG/.4mm
16
130
200
200
200
Data Rates, kb/s
32
130
130
130
200
64
130
130
130
130