en.wikipedia.org/wiki/Companding
1 correction found
This is equivalent to using a non-linear ADC as in a T-carrier telephone system that implements A-law or μ-law companding.
Standard T-carrier/T1 telephony uses μ-law companding, not either A-law or μ-law. A-law is the corresponding scheme used in Europe and other regions, not the usual T-carrier context.
Full reasoning
This sentence overstates which companding laws apply to T-carrier telephony.
A Tektronix primer on T1 / T-carrier states that for voice digitization in the DS1/T1 system, “In North America, this scheme is µ-law (‘Mu-law’) encoding,” and then immediately describes how those 8-bit samples are carried in T1 systems. That directly ties standard T1/T-carrier telephony to μ-law.
The Library of Congress’s format description for µ-Law says it is the “standard companding algorithm used in digital communications systems in North America and Japan,” and adds that “A-Law ... is used in Europe and throughout the rest of the world.”
Putting those together: a T-carrier telephone system is not accurately described as implementing “A-law or μ-law” interchangeably. In the standard T-carrier/T1 telephony context, the companding law is μ-law; A-law is the corresponding regional alternative used outside that context.
2 sources
- T1 Network Technology : Essentials for Successful Field Service Technicians | Tektronix
In the DS1/T1 system ... a non-linear coding scheme was devised ... In North America, this scheme is µ-law ("Mu-law") encoding ... In T1 systems, there are 24 individual 8-bit DS0 samples grouped together into a frame.
- µ-Law Compressed Sound Format | Library of Congress
Description: Standard companding algorithm used in digital communications systems in North America and Japan ... Notes: "Mu-law ... is the encoding scheme used in North America and Japan for voice traffic. A-Law ... is used in Europe and throughout the rest of the world."