5.0 OPERATION
Once you have configured each Model 2065/66RC and connected
the cables, you are ready to operate the unit. This section describes
the LED status monitors, clocking requirements and the power-up
procedure.
5.1 LED STATUS MONITORS
The Model 2065/66RC features seven front panel LEDs that
indicate the condition of the modem and communication link. Figure 8
(below) shows the positions of the LEDs, and the bullets describe their
functions.
• Elastic Buffer - monitors elastic buffer status, and operates only
when the Model 2065/66RC’s RS-232/V.35 port is configured as a
DTE (i.e. the converter is connected between two DCE devices).
When configured in this manner, the two internal 16-bit elastic
buffers are enabled. If either of these buffers becomes full or
empty (due to clock loss or slip), the LED will briefly glow red to
indicate data loss. The buffer will then reset to half-full and the
LED will stop glowing. When the Model 2065/66RC’s RS-232/V.35
port is configured as a DTE, this LED has no function.
• TD (Transmit Data) - indicates status of transmit data at RS-
232/V.35 interface. If the DCE/DTE strap is set for “Converter =
DCE”, then transmit data is an input to the converter. If the
DCE/DTE strap is set for “Converter = DTE”, then transmit data is
an output from the converter. Red indicates a mark or idle state.
Green indicates a space or active state.
• RD (Receive Data) - indicates status of receive data at RS-
232/V.35 interface. If the DCE/DTE strap is set for “Converter =
DCE”, then receive data is an output from the converter.
(continued)
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Figure 8. The Model 2065/66RC front panel, showing LED positions
Model 2066RC
Elastic
Buffer
TD
RD
TC
RC
XC
Cont
Ind
If the DCE/DTE strap is set for “Converter = DTE”, then receive
data is an input to the converter. Red indicates a mark or idle
state. Green indicates a space or active state.
• TC (Transmit Clock) - indicates status of transmit clock at RS-
232/V.35 interface. If the DCE/DTE strap is set for “Converter =
DCE”, then transmit clock is an output from the converter. If the
DCE/DTE strap is set for “Converter = DTE”, then transmit clock is
an input to the converter. Red indicates a mark or idle state.
Green indicates a space or active state.
• RC (Receive Clock) - indicates status of receive clock at RS-
232/V.35 interface. If the DCE/DTE strap is set for “Converter =
DCE”, then receive clock is an output from the converter. If the
DCE/DTE strap is set for “Converter = DTE”, then receive clock is
an input to the converter. Red indicates a mark or idle state.
Green indicates a space or active state.
• XC (External Clock) - indicates status of external clock at RS-
232/V.35 interface. If the DCE/DTE strap is set for “Converter =
DCE”, then external clock is an input to the converter (see Note
1
).
If the DCE/DTE strap is set for “Converter = DTE”, then external
clock is an output from the converter (see Note
2
). Red indicates a
mark or idle state. Green indicates a space or active state.
Note
1
: When configured this way, an external clock output from the
RS-232/V.35 DTE to the converter is not required.
Note
2
: When configured this way, the external clock output from the
converter must be used by the RS-232/V.35 DCE as the clock source.
• IND (Indicate) - glows green when INDICATE from the X.21 DCE
is active.
• CONT (Control) - glows green when CONTROL to the X.21 DCE
is active.
5.2 CLOCKING
The Model 2065/66RC
always connects to an X.21 DCE device. In
all applications the X.21 DCE must supply the system timing.
Consequently, the RS-232/V.35 device (DCE or DTE)
must be
configured to accept an external clock input. Any other equipment
clock settings will likely cause clock slip and/or data loss.
5.2 POWER-UP
There is no power switch on the Model 2065/66RC: Power is
automatically applied to the 2065/66RC when its card-edge connector
touches the chassis' mid-plane socket, or when the chassis' power is
turned on.
Note: The 2065/66RC is a "hot swappable" card—it will not
be damaged by plugging it in or removing it while the rack is powered
up.
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