PRACTICE 297-2011-202
1. INTRODUCTION
1.01 The Business Set is designed for direct connection, through a
non-loaded subscriber loop pair, to the Northern Telecom DMS-250,
DMS-100, or Meridian SL-100 Digital Switching Systems.
1.02 The M5112 12-button Handsfree Business Set will work with a
maximum loop length of 4,572 m (15,000 ft) of 26 AWG standard
twisted pair telephone wires, subject to Line Engineering rules
(297-2011-180). The Set requires a 16 Vac external plug-in type power
supply to be fully operational. If the external power supply fails, the
M5112 Set reverts to basic business set service, i.e. key/indicator pairs
1 to 10 will function normally, while the key/indicator pairs 11 to 12
together with the Headset, Handsfree and Muting features cease to
function. Handset operation is supported without the volume control
capability. Ringer loudness and on-hook dialing voice quality will
suffer some degradation during local power failures. The plug-in
transformer is equipped with an NE-267QA Duplex Adapter which
allows feeding of external power through the line cord to the telephone.
1.03 The service provided by the Business Set substitutes low-level
signals passed over a half-duplex, above-voiceband signaling channel
for the traditional loop signaling (dial pulse) or inband tone signaling
(DTMF tones) on a conventional subscriber loop. In addition to
signaling and supervision, messages on the above-voiceband signaling
channel include signals for implementing the many special features
available on the Business Set.
1.04 The M5112 Business Set offers a choice of selected key and
system features; it has 5 fixed feature keys, two of which have
associated Liquid Crystal Display (LCD) indicators, a dial pad
consisting of 12 fixed keys, 10 programmable feature and/or directory
number keys with LCD indicators, and is equipped with a microphone
and a speaker for Handsfree operation.
PHYSICAL
CHARACTERISTICS 1.05 Fig. 1-1 gives the dimensions and main components of the
Meridian M5112 Business Set. The set comes in three different colors:
(a) Chameleon-grey (NT4X31AA, NT4X31CA, NT4X31EA)
(b) BTS light-grey (NT4X31BA, NT4X31DA, NT4X31FA)
(c) Black (NT4X31GA, NT4X31HA, NT4X31JA)
OTHER
DOCUMENTATION 1.06 Other information pertaining to Business Sets can be found in
the following documents:
297-2001-100
Page 1-1
