4.5
Requesting AB Signalling
When you use this request, you are asking the system to reveal the A and B bits. Upon making the AB
signalling request, the system supplies you with the following information:
•
A bit transmitted to the CO,
•
B bit transmitted to the CO,
•
A bit received from the CO,
•
B bit received from the CO.
4.5.1
Setting The DIP Switches To Request AB Signalling
Set the DIP switches as shown in the following table. Switch 1 is the top switch. When the switch is
moved to the right, it is turned on. Use switches 4 through 8 (designated in the table by A through E) to
select the channel you want to test (1 through 24). See the table in section 4.1.1 for the relationship
between the 24 different letter groups and channel numbers. For remote operation, determine the
corresponding hex code from Table 1.
SWITCH SETTINGS
TYPE OF REQUEST
HEX
CODE
1
2
3
4
5
6
7
8
Provide AB signalling on the channel
designated by ABCDE. See section 4.1.1.
see
Table
1
OFF OFF ON
A
B
C
D
E
4.5.2
Reading The AB Signalling Information From The LEDs
The Table below shows samples of the AB signalling information that is revealed by the LEDs. LEDs 5
through 8 are off. LED 1 is at the top.
LEDs
LED DEFINITIONS
HEX
CODE
1
2
3
4
5
6
7
8
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
LEDs 5-8 are off
Transmitting A bit to central office
Transmitting B bit to central office
Receiving A bit from central office
Receiving B bit from central office
80
40
20
10
Troubleshooting The DXPT1 Installation
IMI89–207
Throubleshooting The DXPT1 Installation – 17