3.2 SETTING INTERNAL DIP SWITCHES
The Model 1110A uses four internal DIP switches that allow
configuration for a wide range of applications. In order to set the
internal DIP switches, you must open the Model 1110A case.
NOTE: Before opening the case, determine whether the default
settings are correct for your application (see Section 3.2.2).
3.2.1 Opening the Case
To open the Model 1110A case, insert a flat head screw driver
between the case lip and DB-25 connector (see Figure 3).
Twist the screw driver head slightly and the top half of the case will
separate from the lower half, as in Figure 4, below.
To set the switches, use a small screwdriver and gently push each
switch to its proper setting. Finally, fit the case halves together and
push to snap closed.
3.2.2 Configuration Switch Set “S1”
The switches on DIP switch S1 are used to set the RTS/CTS delay
and the method of carrier control. Figure 5 shows the orientation of the
switches on DIP Switch S1 with respect to ON/OFF positions.
The default settings for DIP switch S1 are shown in the table below.
Detailed descriptions of each switch follow the table.
Switches S1-1 & S1-2: RTS/CTS Delay
The combined settings for switches S1-1 and S1-2 determine the
amount of delay between the time the Model 1110A “sees” RTS and
then sends CTS to the DTE device. Options are no delay, 9.5 ms and
79.5 ms.
S1-1
S1-2
Setting
Off
Off
No delay
On
On
9.5 ms
On
Off
79.5 mS
On
Off
Not a Valid Setting
5
6
Figure 5. Close-up of DIP Switches Showing “ON” and “OFF” Positions
1
2
3
4
ON
OFF
ON
S1 SUMMARY TABLE
Position
Function
Factory Default
S1-1
RTS/CTS Delay
On
S1-2
RTS/CTS Delay
On
S1-3
Carrier Control
Off
Constant
S1-4
Factory Use Only
Off*
}
9.5 mS
* Indicates Mandatory Setting
Figure 3. Using a small screwdriver to separate the Model 1110A case
Figure 4. Using a small screwdriver to separate the Model 1110A case