fast busy signal

A signal indicating to the calling party that network resources are not available to

process the call. Synonymous with reorder tone. See also busy signal.

• ODU (Optical Data Unit)
• OEM (Original Equipment Manufacturer)
• OEO (Optical-Electrical-Optical)
• OFC (Optical Fiber, Conductive)
• OFCP (Optical Fiber, Conductive, Plenum)
• OFCR (Optical Fiber, Conductive, Riser)
• OFDM (Orthogonal Frequency Division Multiplexing)
• offered load
• off-hook
• off-hook voice announce
• off-premises extension (OPX)
• off-premises station (OPS)
• offset quadrature phase shift keying (OQPSK)
• offshoring
• OFN (Optical Fiber, Nonconductive)
• OFNP (Optical Fiber, Nonconductive, Plenum)
• OFNR (Optical Fiber, Nonconductive, Riser)
• OH
• Ohm, Georg Simon (1787–1854)
• Ohm’s Law
• Ohm’s Law
• OLT (Optical Line Terminal)
• OLT (Optical Line Terminal)
• Omnibus Budget Reconciliation Act of 1993 (OBRA 93)
• OMR (Optical Mark Recognition)