- L-band
- Land Mobile Communications Council (LMCC)
- Land mobile radio
- Land mobile service
- Landline
- LAPB (Link Access Protocol for B-channel)
- LATA (Local Access Transport Area)
- LCD (Liquid Crystal Display)
- Least Significant Bit (LSB)
- LED (Light Emitting Diode)
- Lee's model
- Lifeline/link-Up Services
- Line
- Linear power amplifier (LPA)
- Linear Predictive Coding (LPC)
- Link
- Link budget
- Little LEO
- Local Area Network (LAN)
- Local calling area
- Local exchange area
- Local Exchange Carrier (LEC)
- Local loop
- Local Multipoint Distribution Service (LMDS)
- Local number portability
- Local operator
- Local-State Governmental Advisory Committee (LSGAC)
- Location Area Identity (LAI)
- Location registration
- Logical channel
- Look angle
- LOS (line of sight)
- LOS (loss of signal)
- Lottery/random selection
- Low Earth Orbiting Satellite (LEO)
- Low Noise Amplifier (LNA)
- Low Power Television Service (LPTV)
- lu
- lub
- lur
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