Telecommunications Glossary: ISDN, ADSL, and More

Telecommunications Glossary: Key Terms and Definitions

ISDN (Integrated Services Digital Network)

ISDN is a network defined by international standards.

• ISDN Basic Access: Consists of two 64 Kbps channels and one 16 Kbps channel for signaling to the plant.
• ISDN Primary Access: Provides access to 30 basic channels (2 Mbps).
• Broadband ISDN: Refers to ISDN when the rate exceeds 2 Mbps.
• Narrowband ISDN: Refers to ISDN with speeds ranging from 64 Kbps to 2 Mbps.
• Channel B: ISDN data transmission channel at 64 Kbps.
• Channel D: ISDN signaling channel at 16 Kbps.
• TR1: ISDN Network Termination.

ADSL (Asymmetric Digital Subscriber Line)

ADSL is a broadband service with different rates for upstream and downstream data.

• Microfilter: Low-pass filter for ADSL to allow the voice channel.
• Splitter: Multi-filter for ADSL, used to separate voice and data channels.

Telephone Network Infrastructure

• Cable Drop: Leads to the home phone service subscriber.
• Boxes: Point of concentration and cable connection drop.
• Recording Chambers: Underground cavities that allow operators to work with telephone wires, interconnecting different types.
• Local Central: A switching center linked to a nearby geographical area.
• ICT (Common Telecommunications Infrastructure): Sites and pipelines that new buildings should incorporate to install telecommunications services.
• PABX (Private Automatic Branch Exchange): Telephone switchboard used to meet the switching needs of private entities.
• Outside Plant: Telephone wires and other equipment extending from the PTR to the local exchange.
• Subscriber Network: Consists of telephone wires, rosettes, and equipment comprising the subscriber network, ending in the PTR.
• Telephone Network: All means enabling communication between telephone terminals.
• Main Distribution Frame: The connecting element at the entrance to the telephone system.
• Rosette: Connection point for telephone wires that connect the terminals.

Telephone Equipment and Technology

• Fax: Telephone terminal used to send documents.
• Modem: Responsible for modulating and demodulating the data signal sent over the telephone line.
• Touch-tone: The telephone keypad is assigned a combination of tones for recognition by the system.
• RJ-11: The 6-circuit telephone jack used by telephone terminals.
• RJ-45: The 8-circuit telephone jack used by ISDN telephone terminals.

Telephony

Telephony is an application of electricity that has brought extraordinary consequences for daily life. It is the most used method for two people at a distance to communicate.