Northern Telecom DMS-100 Series General Description, Installation And Maintenance page 28

Chart 2-1 Continued
INSTALL A BUSINESS SET
STEP PROCEDURE
11
Note: The following must be observed when installing an ACD Set:
Applying power. Either the alternate power supply and loop-power must be applied simultaneously
(that means, insert linecord into the ACD Set after the other end of the linecord has been plugged into
the connecting box and the power supply), or the loop voltage must be applied first and the alternate
power source second (that means plugging the linecord into the connecting box before inserting the
plug-in tranformer into the wall-receptacle). Never apply alternate power first and loop power second.
If this is not observed, the following will happen:
- Keypad operation will be loocked out
- Speaker volume controls will be disabled.
Should this condition exist, unplug the linecord at the ACD Set momentarily and then reconnect it.
This will clear the problem.
Tip/Ring polarity reversal. If the ACD Set was installed with wrong Tip/Ring polarity but was
powered up in the correct sequence, the set may work with the following defects:
- Keypad operations will be locked out
- Poor acoustics due to absence of AGC control voltage (LV)
- Loop current detector in linecard would not be able to detect set presence (if BCS
supported).
The only time above condition may happen is at an initial set installation or during wiring
rearrangements at the Distributing Frame when polarity may be reversed inadvertently. To correct the
problem, after polarity has been corrected, simply disconnect linecord at the set momentarily and
reconnect it in the same fashion as when power was applied in the incorrect sequence. This will clear
the problem.
As a general precaution, if there are customer complaints about a malfunctioning ACD set (including
ESD discharges in dry environment), check (and correct, if necessary) polarity and try the linecord
unplugging and reconnecting (at the set) routine before calling repair or returning any set to the
factory.
Internal Option Switches 2.17 Business sets without alphanumeric display have three option
switches: S1, S2, and S3. These switches perform the following functions:
• The S1 Switch is used to set the address of the set. Address 0 is
reserved for the main set, address 4 is reserved for possible extensions.
Presently, extension sets are not in use, and are not supported.
•
The S2 Switch has two sections; one is used to adjust the set to loop
PRACTICE 297-2011-200
Page 2-21