19
Standalone G-Converter
TECHNICAL: 0118 931 2233
Diagnostics
Front Panel LEDs
On the front panel, only the
CARRIER
LED and
POWER
should normally be illuminated.
When the G-Converter is disconnected from the network or has lost carrier the CARRIER
LED will extinguish.
Seven Segment Display
The seven segment LED display can reveal the state of the G-Converter. In normal
operation, the display should be steady indicating the N value of the DCE data rate selected.
If the display flashes “Er” then either the G.703 carrier is lost or the framing can not be
recovered from the incoming data stream. This will depend on the G-Converter set up and
the type of network that it is connected to.
If the display flashes “rL”, then a remote loopback has been initiated from a rack mounted G-
Converter card. In this mode the clock and data are suppressed from the DCE connector.
The DCE data being internally looped back to the rack mounted G-Converter card.
If the display flashes “ Fo” this means that an external clock mode has been selected and the
F
requency of the external clock is grossly
O
ut of range.
If the right most decimal point is permanently on, then the G-Converter has either been set to
be a local unit or it is in local loopback (front panel toggle switch set to the left). If this
decimal point is flashing then the G-Coverter is in an external clock mode.
Loopbacks
The loopback switch is located on the front panel. This switch can be disabled by moving
LK12 jumper to position 2-3. In normal operation, the switch is set in a central position, and
the LOOP LED indicator is not illuminated.
When set to local loop back the received data and transmit data of the X.21 interface are
looped. The DCE clock speed will always be determined by the rotary switch settings
regardless if the unit is set for remote operation.
When set to network loop back the transmit data (TXD) of the G.70x interface is looped
directly to the received data (RXD) of the G.70x interface. The DCE clock speed is
determined by the rotary switches in the case of a local unit and by the data being received in
time slot 31 in the case of a remote unit.
It is possible to apply loop backs either at the X.21 side of the converter or the G.703 link
interface side of the converter. Simple functionality tests may be performed on a single G-
Converter whilst disconnected from the Network.
