H-channel

H-channel: In Integrated Services Digital Networks (ISDN), a 384-kb/s, 1472-kb/s, or 1536-kb/s channel, designated as "H₀", "H₁₀", and "H₁₁", respectively, accompanied by timing signals used to carry a wide variety of user information.

Note: Examples of types of user information representation forms include fast facsimile, video, high-speed data, high-quality audio, packet-switched data, bit streams at rates less than the respective H-channel bit rate[?] that have been rate-adapted or multiplexed together, and packet-switched information.

Source: from Federal Standard 1037C and from MIL-STD-188