This read-only INTEGER identifies the voice encoding type used, returning mu-law for T1 lines and a-law for E1 lines. This confirms which companding law the echo canceler and voice path are operating under, which an admin would cross-check against expectations when troubleshooting audio quality on a specific card. For example, if a card unexpectedly reports a-law encoding on what should be a T1 deployment, an admin would investigate whether the line type was misconfigured.