Switch S1-8: Loopback Test Enable
Depending upon the setting of switch S1-8 the Model 2703 will
either be continually in loopback mode, or loopback mode will be
enabled by pressing and holding the front panel switch. Since the
front panel switch is spring loaded–it returns to “Normal” operation
when pressure is released–this DIP switch provides a way of leaving
the Model 2703 in “unattended” loopback mode for remote test pur-
poses.
S1-8
Setting
On
Continual “unattended” loopback mode
Off
Loopback activation by front panel switch
3.1.2 Switch Set S2 (To be Used in Conjunction with S1-1)
Set DIP Switches 2-1 and S2-2 in unison to determine the UD-26
terminal interface on the Model 2703. The alternatives are V.35 or
EIA-530/X.21. Switches S2-3 through S2-8 are
Reserved for Future
Use
.
S2-1
S2-2
Setting
On
On
V.35 Interface (S1-1 must be “Off”)
Off
Off
X.21/EIA-530 (RS-422) Interface
(S1-1 must be “On”)
3.2 INTERNAL JUMPER SETTINGS
The Model 2703’s seven jumpers are located on the Network
Interface Module PC board inside the unit. To access the jumpers, fol-
low these instructions:
1.
Insert a flat head screw driver into an open slot on either side
of the case. Twist the screw driver head slightly and the top
half of the case will separate from the lower half, as in Figure
3, below.
7
S2 SUMMARY TABLE
Position
Function
Factory Default
S2-1
X.21/V.35
On
S2-2
Terminal Interface
On
S2-3 thru S2-8
Reserved for Future Use
Off
}
V.35
NOTE: The 9/16” Hex nuts must be removed from the front of the
2703 before the Modeule can be lifted up and removed.
2.
Remove the Network Interface Module by lifting gently upward
on it until it comes free from the Model 2703 main PC board.
3. Slide out the Network Interface Module and locate the
jumpers on the bottom side of the board.
4.
Configure the jumpers according to the section below and
return the Network Interface Module and cover to their proper
positions.
8
Figure 4. Jumper locations on Model 2703 PC board.
LK6
LK7
LK5
LK3
LK2
LK4
LK1
Figure 3. Opening the 2703 Case with a Small Screwdriver