Black Box Cable Box May-95 User Manual
15
CHAPTER 3: Configuration
3.1.4 C
ONFIGURATION
S
WITCH
“S3”
Use the individual positions on DIP switch S3 to set antistream control,
receive (input) impedance, and point-to-point/multipoint, as well as to
enable or disable local and remote loopbacks. The factory-default settings are
summarized in Table 3-3 below.
receive (input) impedance, and point-to-point/multipoint, as well as to
enable or disable local and remote loopbacks. The factory-default settings are
summarized in Table 3-3 below.
Table 3-3. Switch S3 Summary
S3-1 and S3-2: Input Impedance
Set positions 1 and 2 of switch S3 to determine the Multi-Function LD Card’s
input impedance.
Set positions 1 and 2 of switch S3 to determine the Multi-Function LD Card’s
input impedance.
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 Multi-Function LD Card: Thicker-gauge cables
require a lower ohm setting, while thinner-gauge cables require a higher ohm
setting. Also, higher data rates call for a lower ohm setting, and lower data
rates dictate a higher ohm setting. Table 3-4 below lists our recommendations
for setting this switch.
of the load (or resistor) of the Multi-Function LD Card: Thicker-gauge cables
require a lower ohm setting, while thinner-gauge cables require a higher ohm
setting. Also, higher data rates call for a lower ohm setting, and lower data
rates dictate a higher ohm setting. Table 3-4 below lists our recommendations
for setting this switch.
S3-1
S3-2
Input Impedance
On
On
130 ohms
On
Off
200 ohms (default)
Off
On
320 ohms
Off
Off
High (minimum 2000 ohms)
Position
Function
Default Setting
S2-1
Input Impedance
On
200 ohms
S2-2
Input Impedance
Off
S2-3
Reserved
N/A
S2-4
Pt.-to-Pt./Multipoint
On
Point-to-Point
S2-5
DTE Local Loopback
Off
Disabled
S2-6
DTE Remote Loopback
Off
Disabled
S2-7
Antistream Control
Off
Disabled
S2-8
Antistream Control
Off