5.0 OPERATION
Once you have configured the Model 1205RC and connected the
cables to host A and host B, you are ready to operate the unit. This
section describes the LED status monitors and power-up procedure.
5.1 LED STATUS MONITORS
The Model 1205RC features 13 front panel status LEDs that indi-
cate the condition of the Model 1205RC and the two ports, A & B (see
Figure 9, above):
• The green “PWR” LED glows green when power is applied to the
Model 1205RC through its mid-plane chassis connection.
• Two “TD” LEDs monitor the status of each port’s data transmis-
sion. The red LED glows when the signal is in an idle (negative)
state. The green LED glows when the signal is in a transmitting
(positive) state. Both LEDs will normally blink when data transmis-
sion is occurring.
• Two “CD” LEDs monitor the status of each port’s carrier detect sig-
nal. The red LED glows when the receive channel is not active
(negative condition). The green LED glows when the receive
channel is active (positive condition).
• Two “DTR” LEDs monitor the status of DTR for each port. The red
LED glows to indicate that the host device connected to that port
is not ready to communicate (negative condition). The green LED
glows to indicate that the host device connected to that port is
ready to communicate (positive condition).
12
Figure 9.
Model 1205RC front panel, showing LED indicators.
Model 1205RC
Power
TD
CD
TD
DTR
CD
DTR
Port
B
Port
A
S1 through S3: Data Rate Setting
Switches S1 through S3 are set in combination to determine the
synchronous data rate for the Model 1205RC. Switch S4 is not active.
S1
S2
S3
S4
Setting
Off
Off
Off
N/A
32 kbps
On
Off
Off
N/A
48 kbps
Off
On
Off
N/A
56 kbps
On
On
Off
N/A
64 kbps
Off
Off
On
N/A
72 kbps
On
Off
On
N/A
112 kbps
Off
On
On
N/A
128 kbps
On
On
On
N/A
144 kbps
3.3 FUNCTION CARD JUMPERS
The Model 1205RC has two ports (Port A and Port B), and each
must be configured independently. Therefore, every function (such as
clocking) has two jumpers associated with it. As Figure 3 (below)
shows, each jumper has three possible positions: strap covering posts
1 & 2, strap covering posts 2 & 3, or strap removed altogether. The
detailed description for each jumper presents all valid strap positions.
5
Figure 2.
Model 1205RC DIP switch orientation on internal daughterboard.
On
4
3
2
1
Top of Card
Figure 3.
Possible function card strap positions
1
2
3
Front of Card
1
2
3
1
2
3
