AT&T AT&T manual Single-Line Voice Terminals, Model 500 Series, Pft

Terminal Equipment

Terminal equipment is connected to System 25 station (voice or data) ports. It is made up of the following groups:

●Voice Terminals

—Single-Line

—Multiline (MERLIN sets and MET sets)

●Voice Terminal Adjuncts

●Attendant Consoles

●Asynchronous Data Units (for interface with data terminals).

This subsection	provides information on all components in each group or contains references
to the Section	where information can be found.

Voice Terminals

System 25 supports a wide range of voice terminals, including industry standard touch-tone single-line sets and MERLIN rnultiline sets.

In addition to providing basic telephone service (placing and answering calls), voice terminals can also be used to activate many system features. The voice terminals supported by System 25 are listed in Table 4-Cand described in individual subsections.

Single-Line Voice Terminals

Single-1ine voice terminals can have only one call appearing at the terminal at a time.

All information (voice and control signals) transmitted to and from a single-line voice terminal is in analog form over a single pair of wires (called tip and ring). Power for these voice terminals is also provided over this pair. The ZTN78 Tip Ring Line CP or TN742 Analog Line CP converts the analog signals to digital format before placing them on the TDM bus. The dial pad on the single-line voice terminals is a touch-tone pad that generates Dual Tone Multifrequeney (DTMF) signals.

The following subsections provide descriptions and illustrations of the single-line voice terminals supported by System 25.

Model 500 Series (V2)
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	55A1 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 4-4except for their rotary dials.

●Model 500MM-Basic desk set

●Model 500SM—Desk set with 4A Speakerphone compatibility

●Model 554BMPA—Basic wall set.

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