Glossary

CA	Customers Apparatus.
CA (PSTN fault location)	Customer Apparatus. Fault located at customer apparatus (appointment required).
CE (PSTN Fault Location)	Customers End. Fault located between DP and customer apparatus. Note: Although CE means fault found at “Customers End”, this does not require an engineer visit.
CLI	Calling Line Identity (also known as Caller ID, caller identification, CID, Calling Number identification, or CNID). A telephone service that transmits a caller’s number to the receiving telephone equipment during the ringing signal, or when the call is being set up, but before the call is answered. May also refer to ‘Customer Lead In’.
CP	Communication Provider.
CPE	Customer Premise Equipment – The equipment that resides on the customer’s premises, such as a PBX or IAD.
CRD	Customer Required Date. The date on the customer requirement form when a customer needs the service to be activated or installed.
CSC	Customers Service Centre.
CSE	Customers Service Engineer.
DN	Directory Number – A unique complement of digits associated with the name of a subscriber in a telephone directory – i.e. your phone number.
DOA	Dead on Arrival.
DPA	Duct and pole Access.
DTMF	Dual Tone Multi-frequency – Also known as Touch-tone, it is the signal generated when you press a telephone’s touch keys that is sent to the telephone company. These signals are actually two tones of a specific frequency designed so that a voice cannot duplicate them. The ability for interactive telephone menus to work correctly across different networks and phone systems is due to the fact that DTMF tones are standardised and are uniquely linked to a number (and # or *) on the telephone keypad.
EU	End User. The final consumer of a product; the intended recipient or user.
FBC	Field Based Coordinator.
FU (PSTN Fault Location)	Field Unit. Fault located at exchange on the Openreach side of MDF.
ISDN	Communication Provider.
CP	Integrated Services Digital Network – A switched network providing end-to-end digital connectivity for simultaneous transmission of voice and/or data over multiple multiplexed communications channels, and employing transmission and out-of-band signalling protocols that confirm to internationally-defined standards.
IVR	Interactive Voice Response – An integrated software information system that speaks to callers and uses menus and voice responses. By using touch-tone keypad entries to interact with the software, you get voice responses with real time data.
Jitter	Jitter occurs when internet routers take slightly different times to transfer data from one place to another.
Latency	The time it takes for a packet to reach its destination.Higher delay times can be an issue, especially for VoIP, where voice delay can be recognized with latency higher than 150 milliseconds. Higher than 500 milliseconds and the conversation is going to be very problematic.
LN (PSTN Fault Location)	Local Network. Fault in the Openreach network.
LO	Line Optical (Fault found from FTTC Cab to Exchange).
LORN	Linked Order Reference Number. Used to link the two orders together in our computer systems to switch broadband and telephone services over on the same day.
LTOK	Line Test OK.
MBORC	Matters Beyond Our (Openreach) Reasonable Control.
NAT	Network Address Translation – An Internet standard allowing a local network to use one public IP address to connect to the Internet and a set of local IP addresses to identify each PC or device in the local network.
NDT	No Dial Tone.
OLO	Other Licensed Operator.
OOH	Out Of Hours.
OR	Openreach.
ORDI	Openreach Data Integrity.
PBX	Private Branch Exchange. A telephone exchange that serves a particular business or office.
PORT	The port used by the phone or ATA to connect to our cloud server. Normally 5060/5061 but may be moved to 7000.
POTS	Plain Old Telephony Service (also known as an analogue telephone line). The basic services provided over the Public Switched Telephone Network (PSTN).
RID	Retailer ID. Used to identify communication providers when placing broadband and telecom orders.
PSTN	Public Switched Telephone Network. It was originally a network of fixed-line analogue telephone systems but the switching (or telephone exchange) element of the PSTN is now digital. The mobile telephony networks are considered to be part of the PSTN.
SIP	Session Initiation Protocol – is a signalling protocol for Internet conferencing, telephony, and instant messaging. It is a request-response protocol, dealing with requests from clients and responses from servers.
SIP Trunks	Is the use of VoIP to facilitate the connection of typically a PBX to the Internet, where the Internet replaces the conventional telephone trunk, allowing a business to communicate with traditional PSTN telephone subscribers worldwide by connecting to an ITSP (Internet Telephony Service Provider).
SNDDI	Single Number Direct Dialling In. An individual number DDI range, which means that for incoming calls the network will send, as default, 6 routing digits to the customer equipment so that calls can be directed to the correct channel.
Soft Phone	IP telephony software that allows end users to send and receive calls over the computer or handheld device over the Internet. Typically used in conjunction with a headset and microphone.
STUN	Simple transversal of UDP through NATs – is a protocol for assisting devices behind a NAT firewall or router with their packet routing.
WLR	Wholesale Line Rental – the name for Openreach copper access product, predominantly used for delivering voice services. The latest generation of WLR is known as WLR3.