S3-1 and S3-2: Input Impedance
, determines 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. The table 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)
S3-4: Mode Selection
, determines whether the Multi-Function LD Card operates in point-to-point or multipoint mode.
S3-4
Operation:
ON
Point-to-Point (also multipoint as the "master") (default)
OFF
Multipoint (as a "slave")
S3-5: DTE RS-232 Initiation of Local Loopback Test
, determines whether or not the attached DTE can initiate the Multi-Function LD Card's local analog loopback test by raising the Local Loopback (LL) signal on Pin 18 of the RS-232 interface.
S3-5
DTE Initiation of Local Loopback:
ON
Enabled
OFF
Disabled (default)
S3-6: DTE RS-232 Initiation of Remote Loopback Test
, determines whether or not the Multi-Function LD Card's remote analog loopback test can be initiated by raising the Remote Loopback (RL) signal on Pin 21 of the RS-232 interface.
S3-6
DTE Initiation of Remote Loopback:
ON
Enabled
OFF
Disabled (default)
S3-7 and S3-8: Antistream Control,
determines the timeout period for the Multi-Function LD Card's antistream-control timer, or to disable the timer entirely.
S3-7
S3-8
Setting:
OFF
OFF
Disabled (default)
OFF
ON
12.5 Seconds
ON
OFF
50 Seconds
ON
ON
12.5 Seconds
Setting the Jumpers on the Interface Module:
Before you install the Card, you should examine the interface module you have selected and make sure that it is configured for your application. Each interface module has three jumpers on its circuit board. The possible settings of the Multi-Function LD Card's
jumpers can be either on pegs 1 and 2 or on pegs 2 and 3. These jumpers determine various grounding and signal characteristics for the serial and modem-to-modem lines. The positions of the jumpers can be viewed on the first page for the interface module.
Line Interface: Line Shield Connection to Frame Ground (JB2):
This jumper applies to the line interface. When this jumper is in positions 1 and 2, it links RJ-11 Pins 1 and 6 on the corresponding line to the interface module's frame ground. (If you are using shielded twisted-pair cable, the shield can be connected to these pins.)
In positions 2 and 3, RJ-11 pins 1 and 6 remain connected to each other, but are disconnected ("lifted") from frame ground.
JP2:
Positions 1 and 2 = Line Shield and FGND Connected
Positions 2 and 3 = Line Shield and FGND Not Connected (default)
CAUTION:
If you connect shield to frame ground, make sure that RJ-11 Pins 1 and 6, as well as the cable shield,
are connected to ground at one end of the cable only. Connecting them at both ends of the cable will
defeat the transformer isolation and will leave your system open to damage from ground loops.
Cable
Gauge
Data Rates in Kbps
1.2
1.8
2.4
3.6
4.8
7.2
9.6
14.4
19.2
28.8
38.4
57.6
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
200
200
200
200
200
200
130
200
200
200
130
130
200
200
130
130
130
200
130
130
130
130
130
130
130
130
