Horizon Glossary

ADSL (Asymmetric Digital Subscriber Line)

Asymmetric Digital Subscriber Line is the common name given to the type of technology used to provide an internet connection to the premises that is always on. This technology does not utilise the full capacity of an analogue line meaning that it is still possible to make voice calls over the line.

ALG (Application Level Gateway)

SIP ALGs are found in many routers or firewalls. They typically inspect SIP traffic as it passes through the router rewriting LAN IP addresses with public IPs. This is a feature that MUST be disabled for use with Horizon.

Assured

Assured broadband is a managed broadband service offered by Gamma. Gamma will guarantee a selected amount of calls over Gamma VOIP products. A pre-configured Cisco router will be provided that can be managed by Gamma and this allows end-to-end management over the VOIP solution. 

There are five ser:vice options provided. 

Assured 5 guarantees up to 5 voice channels (@ G.729), delivered over ADSL 2+ Annex A

Assured 10 guarantees up to 10 voice channels (@ G.729), delivered over ADSL 2+ Annex A 

Assured 15 guarantees up to 15 voice channels (@ G.729), delivered over ADSL 2+ Annex A

Assured 20 guarantees up to 20 voice channels (@ G.729), delivered over ADSL 2+ Annex A

Assured 30 guarantees up to 30 voice channels (@ G.729), delivered over ADSL 2+ Annex A 

Please note that Assured circuits must be dedicated for VOIP only, and no data services can be used.

Hardware device that allows analogue phones to be connected to the Horizon system.

BLF (Busy Lamp Field)

A Busy Lamp key gives you the ability to monitor a colleague’s line to see if they are available to take a call that you may transfer to them, or to enable you to pick up their calls if part of a Call Pickup Group.

When implemented, the phone will show the user’s caller ID on the pre-defined line keys on your device. This line key can also be used as a speed dial.

Cisco

Hardware vendor used by Gamma for the supply of handsets and Assured routers.

CLI FLEXIBILITY

CLI PRESENTATION

See Site DDI

CUSTOMER PREMISES EQUIPMENT (CPE)

This refers to all the hardware on the LAN side of the network (i.e handsets, router, switches, PBX).

Handsets will be specialised for use on their respective products and will be sent pre-configured by Gamma.

The supply, provisioning and support of all other hardware at the customer’s site is the responsibility of the Channel Partner. It is up to the channel partner to ensure the router is correctly configured as per the requirements for service as detailed on the Knowledge Base.

CODECS

Codecs are used to convert an analogue voice signal to a digitally encoded version. Codecs vary in the sound quality, the bandwidth required, the computational requirements, etc. Each service, program, phone, gateway etc. typically supports several different codecs, and when talking to each other, negotiate which codec they will use.

The maximum number of concurrent channels = the available bandwidth/total bandwidth, so if for example a customer has a 512 kbps upload line speed, assuming no contention, using G.729 with a sample period of 20ms there will be 512/40 ≈ 10 usable concurrent channels available.

Generally, G.729 is the preferred VoIP codec (the algorithm that encodes and decodes analogue voice to and from digital) when access is via ADSL, owing to its efficient use of bandwidth, whilst still providing good audio quality.

Gamma Supports G711alaw, G711ulaw and G729.

CALL QUALITY

See packet loss, jitter, codecs

DDI (Direct Dial In)

DDI (Direct Dial In) is a service that provides a block of telephone numbers for calling into a company’s VOIP system. Using DDI, a company can offer its customers individual phone numbers for each person or workstation within the company without requiring a physical line into a PBX for each possible connection.

DO NOT DISTURB (DNR)

Do Not Disturb (DND) allows users to set their phone as unavailable so that incoming calls are given a busy treatment. Users have the option to activate and deactivate the service by dialling a feature access code, by configuring the service via their web interface, or by pressing the DND button on phones which support it.

This can be activated and deactivated using the handset directly (if applicable), the voice portal or the GUI.

HORIZON PORTAL

This is the interface where you will configure and manage your horizon service. There are 2 layers to the Horizon portal;

User Level – Each user on the Horizon platform will have access to the user-level portal. Here they will be able to set up their call handling and directory for their handset. 

Admin Level – This is where the company-wide call handling will be set up. You can manage the users, hunt groups and a wide range of other call-handling tools to meet the customer’s needs.

JITTER

Variation in delay. The effects of jitter can be mitigated by storing voice packets in a jitter buffer upon arrival and before producing audio.

LATENCY

The amount of time it takes for a packet to travel from its source to its destination and back again. High latency can be a contributing factor to poor-quality audio over VOIP.

PACKET LOSS

Occurs either in bursts or due to a congested network. Periodic loss in excess of 5-10% of all VoIP packets can degrade voice quality significantly.

POE

Power Over Ethernet handsets have the option of being powered via an Ethernet cable rather than by a power supply unit. This required the supply of a POE switch by the Channel Partner/End User.

POLYCO

A hardware manufacturer that supplies handsets for use on Horizon.

Each Horizon handset has a URL provisioned that will allow it to download its configuration. DNS must be enabled on the network for this to work.