INSTALLATION & SET-UP
8
Note:
On older units, bit-switch 7 enabled the transmission of the MAC FCS. This feature
has now been removed.
3 . 1. 2 Timing
TIMING
determines the source for the LINE transmit clock, and is set by bit-switch No1. The
options are
ON
or
OFF.
With the switch set to
ON
, the transmit clock is derived from the WC3445's own internal
oscillator.
With the switch set to
OFF
, the transmit clock is derived from the LINE receive
clock.
3 . 1. 3 E3/DS3 Port Select (BNC)
This single switch is used to select which type of interface (E3 or DS3) is to be used to
connect the line.
With the switch set to
ON
, the E3 port is selected to give a G.703 75 ohm unbalanced
34.368 Mbps interface.
With the switch set to
OFF
, the DS3 port is selected to give a G.703 75 ohm balanced
44.736 Mbps interface.
3 . 1. 4 Loopback test
This switch is used to initiate loop testing. It is fully described in the next section.
The switch is set to
ON
for normal operation (NONE) of the unit without any loopbacks.
With the switch set to
OFF
, Loopback is applied, so that Transmitted data = Received data
on the WAN port.
3 . 1. 5 Cable length
With switch set to
ON
the output is reduced for operation with shorter cables of length up to
225 feet (69 metres) .
With switch set to
OFF
higher power is used for longer cables of 225 - 450 feet. This applies
to DS3 only.
3 . 1. 6 LAN Mode
Bit-switch
ON:
100 Mbps Full Duplex operation.
Note that this option enables 100M full duplex connection to be implemented. Auto-negotiate
does not distinguish between full versus half duplex modes when negotiating with a fixed
(i.e. non-negotiating) 100Mbps port.
Bit-switch
OFF:
Auto-negotiate Mode (default).
3 . 1. 7 Auto MDI/MDI-X
With switch set to
ON
, the LAN ports are fixed as MDI-X for direct connection to a PC. This
may be necessary for reliability when connecting some older non-auto hubs
With switch set to
OFF
, the LAN ports automatically sense the interface and switch between
MDI and MDI-X connections.
