Black Box ME475A - Input Impedance and Mode Selection; Loopback and Anti-Stream Control

POSITION: FUNCTION: FACTORY DEFAULT:
S3-1 Input Impedance ON 200 ohms
S3-2 Input Impedance OFF 200 ohms
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 Disabled
S3-8 Anti-Stream Control OFF Disabled
Switches S3-1 and S3-2: Input Impedance determines the modem's 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 modem. Thicker-gauge
cables require a lower ohm setting, while thinner-gauge cables require a higher ohm setting. Higher speeds require a lower ohm setting, and slower speeds
require a higher ohm setting.
S3-1 S3-2 Setting:
ON ON 130 ohms
ON OFF 200 ohms
OFF ON 320 ohms
OFF OFF High Impedance (minimum 2k ohms)
S3-3: Not Assigned Yet.
S3-4: Mode Selection 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"
S3-5: Rs-232 Initiation of Local Loopback Test determines whether or not the modem's 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
S3-6: RS-232 Initiation of Remote Loopback Test determines whether or not the modem's remote digital loopback test can be initiated by raising pin 21
on the RS-232 interface.
S3-6 Setting:
ON RS-232 initiation enabled
OFF RS-232 initiation disabled
S3-7 and S3-8: Anti-stream Control are set in combination to determine the timeout period for the modem's antistream control timer.
S3-7 S3-8 Setting:
OFF OFF Disabled
OFF ON 12.5 seconds
ON OFF 50 seconds
ON ON 12.5 seconds
Cable
Gauge
Data Rate (Kbps)
1.2 1.8 2.4 3.6 4.8 7.2 9.6 14.4
19
22
24
26
320
320
320
320
320
320
320
320
200
320
320
320
200
200
320
320
200
200
200
320
200 200 130
200 200 200
200 200 200
200 200 200
Cable
Gauge
Data Rate (Kbps)
19.2 28.8 38.4 57.6
19
22
24
26
130
130
200
200
130
130
130
200
130
130
130
130
130
130
130
130