Instruction manual

HARDWARE DESCRIPTION
Single-Line Voice Terminals
Single-line terminals can have only one incoming call ringing when the terminal is idle. The
user at any busy single-line terminal can put an active call on hold and either originate a call
or answer a waiting/camped-on call. Single-line terminals have access to most system
features that do not require operation of programmable buttons.
All voice and control information between single-line terminals and the system digital switch
is transmitted in analog form on tip and ring pairs of wire (one pair per terminal). Port
circuits (ZTN78 Tip Ring Line CP or TN742 Analog Line CP) in the switch provide
analog/digital conversion. Power for terminals is also sent from the switch on the tip and ring
pairs.
The pushbutton dials on single-line sets (except for the 500 Series) are touch-tone
pads, which generate Dual Tone Multifrequency (DTMF) signals. The rotary 500 sets
generate dial pulses.
The following subsections provide descriptions and illustrations of the single-line voice
terminals supported by System 25.
500 Series
The Model 500 Series consists of conventional rotary dial telephones. They are
recommended for use as a Power Failure Transfer (PFT) stations if the PFT trunk does not
support touch-tone dialing.
A KS 23566,L1 Ground Start button must be used with these
sets if the PFT trunk is ground start. Rotary set users cannot do any procedures that require
pressing the ✶ or # buttons.
The following 500 Series sets are supported by System 25;
these sets are similar in appearance to the 2500 sets shown in Figure 4-4 except for their
rotary dials.
● Model 500MM—Basic desk set (PEC 3100-0RD)
● Model 500SM—Desk set with 4A Speakerphone compatibility (PEC 3100-2RD)
● Model 554BMPA—Basic wall set (PEC 3100-0RW).
2500 Series
The following 2500 Series voice terminals have the following components and features:
● Handset
● Touch-Tone Dial
● Ringer Volume Control.
Several 2500 Series voice terminals are shown in Figure 4-4. System 25 supports the
following 2500 Series sets:
● Model 2500DMGC—Desk Set with message waiting indicator and Recall button for
timed switchhook flash (PEC 3178-SYS)
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