The Marconi IFR Aeroflex 2851 Data & PCM Digital Analyzer is a dual-function test instrument for digital communication and PCM transmission systems. It combines data circuit and PCM rate testing in a single platform, supporting bit rates from 50 bit/s to 2.5 Mbit/s with optional extensions to 8 Mbit/s. The instrument generates and receives PCM framing systems across European and North American digital hierarchies, handles both framed and unframed operation, and includes programmable error generation, alarm simulation, and automatic frame alignment test sequences.
Technical Specifications
-# Data and PCM Rate Testing
• Bit rate range: 50 bit/s to 2.5 Mbit/s in 1 bit/s steps
• Standard rates: 64 kbit/s, n × 64 kbit/s, 2048 kbit/s, 8448 kbit/s
• Optional rates: 1544 kbit/s (T1) or 704 kbit/s
• Extended range: up to 8 Mbit/s; up to 34 Mbit/s (2853S model)
• Framing support: Framed and unframed operation at primary and secondary PCM rates
-# PCM Framing Systems
• 2048 kbit/s: G.704, G.704 no multiframe, G.704 with CRC, G.704 with CRC no multiframe, G.704 32 frame multiframe
• 1544 kbit/s: T1, T1 no signaling, T1ESF, T1ESF no signaling, T1DM, DDS Data Mux
• 8448 kbit/s: G.742 asynchronous, G.745 asynchronous, G.704/741 synchronous, G.704/744, 120 channels synchronous
• 3152 kbit/s: DS1C mode 1 synchronous, DS1C mode 2 asynchronous
• 6312 kbit/s: DS2 96 channels synchronous, DS2 asynchronous, 2048 kbit/s interworking to G.747
-# Data Interface Testing
• RS-232, X.21, RS-449 (V.36), V.35
• Codirectional and contradirectional operation (2850B and 2851)
– Key Features
• Programmable frame or code error generation for equipment threshold testing
• Alarm condition simulation and detection across multiple framing systems
• Automatic test sequences for frame and multiframe alignment validation
• All unassigned frame bit control and display
– Compatibility & Integration
Supports both European and North American digital hierarchies in European, hybrid, and all bit rate versions.
