isdn

isdn — noun

1. a set of rules for sending sound, images, and computer data at high speed throug

1.名詞B2
釋義

a set of rules for sending sound, images, and computer data at high speed through the copper wires of a telephone network — used mainly in the 1990s and 2000s before faster internet connections became common.

例句

The publishing house used an ISDN line to send large image files to the printer.

ISDN + noun (ISDN line)

Xiu remembered how slow the internet felt before her office switched from ISDN to broadband.

同義詞
  • broadband

    a broader, more modern term for any high-speed internet; ISDN was a specific early form of broadband

  • DSL

    a later digital technology that also uses phone wires but offers much higher speeds than ISDN

反義詞
  • dial-up

    an older, slower technology that uses the same phone wires but cannot carry voice and data at the same time

文法句型

ISDN + noun (e.g. ISDN line, ISDN connection)

用法筆記

ISDN is typically uncountable (ISDN is a standard). When used attributively before another noun — ISDN line, ISDN connection — no article is needed. The technology has largely been replaced by DSL, cable, and fiber-optic broadband, so examples commonly appear in past-tense or historical contexts.

常見錯誤

❌I need to buy an ISDN' (countable error).
✅I need an ISDN connection.
💡ISDN is an uncountable noun referring to a standard; you need a second noun (line, connection, service) for countable use.

2. the short form of the words 'Integrated Services Digital Network' — a digital te

2.名詞B2
釋義

the short form of the words 'Integrated Services Digital Network' — a digital telephone network that can send sound, images, and computer information at the same time over standard phone wires.

例句

ISDN stands for Integrated Services Digital Network, a telecommunications standard from the 1980s.

stands for + full name

The job advertisement asked for experience with ISDN, short for Integrated Services Digital Network.

short for [full name]

同義詞
  • acronym

    a broader category; ISDN is one example of an acronym, pronounced as individual letters or as a word

  • initialism

    a term for abbreviations spoken letter by letter, though ISDN is often said as a word /ˈaɪzdən/

文法句型

ISDN stands for [full name]

用法筆記

This sense is relevant only when the speaker is explaining or expanding the acronym itself. In most everyday contexts (e.g., 'Do we have ISDN?') the TECHNOLOGY STANDARD sense applies. The full expansion is always capitalised: Integrated Services Digital Network.