“All-In-One” music-on-hold devices for analog phones, these are the regular  1 to 4 line telephones 

The corded or cordless 1-Line, 2-Line or 4-Line telephones available on-line or in stores.

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Here are some examples:

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AT&T (TL88102) Dect 6.0,  AT&T ML17928, ML17929, AT&T TL86109 … plus all other AT&T phones

VTech DS6151,  CS6529-4, CS6719-2, CS6429-3, IS8151-5 …plus all other Vtech phones

RCA 25201RE1, 25055RE1, U1100, ViSys 25424RE1 …plus all other RCA phones

Panasonic KX-TG9541B, KX-TGF575S, KX-TGF372S …plus all other Panasonic phones

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