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Equipment requirements
553-2691-100 Standard 8.00 August 1996
Standard 500/2500 and SL-1 telephones
Message Waiting Indication cannot be provided visually at these telephones.
The user must call the Message Center by dialing the Message Center DN to
check to see if there are any messages.
If the system is equipped with X11 Release 2 or later, AMW can be provided
when the user goes off hook in the form of an interrupted dial tone (120 ipm).
The user can then dial the Message Center DN and collect the message. In the
case of the 500/2500 telephones, the interrupted dial tone form of message
indication reduces the hardware requirements of the system. In the case of the
SL-1 telephone, it makes an extra feature key available for other uses.
Message Waiting lamp requirements
If the neon bulb of a 500 or 2500 telephone needs to be replaced, customers
should order replacements from Northern Telecom. The bulbs may be
ordered using number A0250554. To avoid potential problems, bulbs must
meet the following criteria:
— Ignition voltage: The bulb must light when a voltage of 90
±
2 V dc is
applied.
— Extinguishing voltage: The bulb must extinguish when the applied
voltage is reduced to 60
±
2 V dc.
— Power consumption: When a resistance of 30 K ohms is placed in series
with the bulb, the power consumption of the bulb must be no more or less
than 0.25 W when operated at 90
±
2 V dc.
If the bulbs installed in a 500 or 2500 telephone do not meet the criteria listed
above (for example, if resistance is higher than recommended), the system
may see the bulb as being faulty and give a misleading indication to the
Message Center operator or disable the feature, or both.
Equip.bdy Page 18 Thursday, December 19, 1996 2:55 PM
