The Motorola R-1151A Code Synthesizer II is a versatile telecommunications test device used to generate various audio tones and digital codes for radio system testing, supporting functions like single/two-tone paging, DTMF, MTS, IMTS, and POCSAG, acting as a test tone generator for simulating mobile/radio signaling and coded squelch (PL/DPL) in professional radio communications. It features analog (sinewave) and digital (square wave) outputs with selectable modes, offering precise frequency generation for aligning and troubleshooting radio systems. 
Key Features & Functions
Multiple Modes: Generates single tones, two-tone sequential, 5/6-tone, DTMF, MTS (Motorola Tone Signaling), IMTS (Improved Mobile Telephone Service), and digital paging (GSC, NEC, POCSAG, SGP).
Coded Squelch: Supports PL (Private Line) and DPL (Digital Private Line) generation.
Analog & Digital Outputs: Provides sinewave analog output and band-limited square wave digital output, with adjustable levels for both.
Frequency Accuracy: Offers 0.1 Hz frequency resolution with 0.5% accuracy over temperature.
Power: Operates on universal AC input (90-135V or 200-240V, 50/60 Hz).