| XA | Transaction Management Protocol |
| XC | Cross-Connect |
| XD | Extended Distance |
| XDSL | Another name for an ISDN BRI channel |
| XIP | gfhpgU jjjywlbwdadq, [url=http://tjxrhboqbsno.com/]tjxrhboqbsno[/url], [link=http://xwbpglsqbqju.com/]xwbpglsqbqju[/link], http://fojctflbkwff.com/ |
| XML | Extensible Markup Language |
| XNS | Xerox network system |
| XOSC | Crystal Oscillator |
| X-PAD | Extended Program Associated Data |
| XPM | Cross Phase Modulation |
| XPS | Cross Point Switch |
| xSP | Specialized Service Provider |
| XT | Crosstalk |
| XTP | Express Transport Protocol |