ISDN Glossary

BONDING - Bandwidth ON Demand INteroperability Group - a method for combining multiple B-channels into a single data stream.

CCS - Common Channel Signaling. This means all signaling goes over a common channel, which is separate from the data channel. Using SS7, ISDN keeps the signalling separate from the B-channels, which gives both faster dialing, and the full 64Kbps. Parts of the country that haven't switched to SS7 can only offer 56Kbps. CCS also sometimes stands for Clear Channel Service, with the exact same meaning..

CPI - Customer Premises Installation - the phone network within the home or business.

CSD - Circuit Switched Data. Phone calls, with data only.

CSV - Circuit Switched Voice. This is traditional phone service.

DOSBS - Data Over Speech Bearer Service. A configuration where the phone company expects you to be using the channel for voice, but you can send data. Also called DOVBS, V for voice. It seems this is used when your local phone company is unable to properly deal with data calls, because their equipment is ancient.

DS1 service - A standard service in the U.S. phone network, running at approximately 1.544 Mbps, capable of handling 24 standard audio phone calls.

E1 service - A standard service in the European phone network, running at approximately 2.048 Mbps, capable of handling 31 standard audio phone calls.

IDN - Integrated Digital Network, the phone company's digital network. It provides digital service within and between all phone companies, but not to the cutomer's door.

POTS - Plain Old Telephone System. Pre-ISDN equipment.

PPP - Point to Point Protocol. An IETF standard for transmitting IP traffic across dialup connections. PPP has been accepted as the standard for IP over ISDN. PSD - Packet Switched Data. For using ISDN with X.25, or things like that. This won't be very common.

National ISDN - A set of interoperability standards being developed in the U.S. so that all the different vendors and phone companies can make equipment that works together.

NI-1(or NI-2, NI-3) - See National ISDN

N-ISDN - More commonly stands for National ISDN, less commonly for Narrowband ISDN.

SDH - is the European equivalent of SONET. They are not the same, but they are close enough that the hardware manufacturers can make equipment that conforms to both standards at the same time.

Signaling - the exchange of information for call setup and control. Sends information on the phone network regarding phone numbers, busy status, call interruptions, hangups, etc. The grating tones that a touch tone phone makes are part of signalling - they are interpreted by the local phone company as a phone number.

SONET - is a standard that defines how data flows across fiber optics. The phone companies uses SONET internally to move lots of data around. They also use SONET to provide service to customers. If you get a SONET link from the phone company, it looks like they've given you your very own dark fiber. In fact, you may be sharing a physical fiber with other people, but the way SONET is defined, you'll never know.

SPID - Service Profile ID. These identify to the phone company what types services and features are supported for a given device. SPIDs are optional in the ISDN standard, but usually required in North America.

Switching - the process of connecting a phone call by connecting lines, or logical channels to each other to form a complete end-to-end connection.

TEI - Terminal Equipment ID. These uniquely identify each each TE device. This ID is dynamically allocated when the TE is attached to the network.

V.110 - A standard for rate adaption for TA equipment.

V.120 - A standard for rate adaption for TA equipment.

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