Manuel d'utilisation / d'entretien du produit D11624 du fabricant TANDBERG
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Video on Frame Relay Tandberg D11624 rev 01.
Tandberg Video on Frame Relay D11624 rev. 01 2 Table of Contents 1. Introduction ............................................................................................................................................... 3 2. Background on transmission of video over frame relay .
Tandberg Video on Frame Relay D11624 rev. 01 3 1. Introduction This document is designed as an 'eye-opener' to video over frame relay and the idea is to show a solution that works. The equipment described in this document is the VFX-250S, a framer unit from Science Dynamics Corporation.
Tandberg Video on Frame Relay D11624 rev. 01 4 2. Background on transmission of video over frame relay The successful transmission of digitised voice over public frame relay data services the past few years has drawn attention to the question of whether video services can be transmitted over the same link.
Tandberg Video on Frame Relay D11624 rev. 01 5 3. Technical issues There are two potential technical issues, which may affect the quality of packetised, digitised video. One is delay, or more properly jitter. Jitter is the variation in delay from one frame to the next.
Tandberg Video on Frame Relay D11624 rev. 01 6 Cell based systems cut packet into fixed sizes Dropped frames are potentially a more serious problem. The frame relay standard allows the network service provider to control congestion by simply disposing of any frames which exceed the users CIR.
Tandberg Video on Frame Relay D11624 rev. 01 7 2. The second method is to establish a traffic prioritisation scheme for any channels carrying video through a FRAD (Frame Relay Access Devices) on a defined DLCI. This ensures that video frames are first out.
Tandberg Video on Frame Relay D11624 rev. 01 8 framer both at the ACT-recommended setting of 256 bytes and at 1.500 bytes (which is in line with the recommendations of other framer users) without any difference in the overall performance. You can connect either the VFX-250S or the ABL VT2C directly to a DSU/CSU on a frame relay network.
Tandberg Video on Frame Relay D11624 rev. 01 9 6. Application Overview The diagram below shows the use of the VFX-250S in a video-conferencing over frame relay application.
Tandberg Video on Frame Relay D11624 rev. 01 10 7. Technical Specification of VFX-250S 7. 1 Network & User Interface Connector: Female 37-pin D type to user equipment (Video codec) Male 37-pin D type to network equipment (FRAD) Interface: RS449 (X.
Tandberg Video on Frame Relay D11624 rev. 01 11 • 4 configuration entries, each of which contains TX and RX DLCI settings, User Clock Speed, Packet Length, and AVB • LMI type control selection &am.
Tandberg Video on Frame Relay D11624 rev. 01 12 8. Approvals FCC Class A Digital Devices and Peripherals This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules.
Tandberg Video on Frame Relay D11624 rev. 01 13 10. Economics of Video over Frame Relay The economics of video over frame relay are similar to those driving the use of voice over frame relay. Voice over frame relay is fairly well accepted as being economical when used in international applications.
Tandberg Video on Frame Relay D11624 rev. 01 14 11. Appendix A: Cables and Pinouts 11. 1 Standard Console Cable The console port on the VFX-250S conforms to EIA-232/V.
Tandberg Video on Frame Relay D11624 rev. 01 15 11. 2 Standard EIA-449/RS449 Cables 11. 2 .1 Network Cable 11. 2 .2 User Cable A note about RTS signalling: Some manufacturers state that their network interface is RS449 (which uses RS422 signalling levels) but actually use RS423 signals for the control leads.
Tandberg Video on Frame Relay D11624 rev. 01 16 11. 3 Standard EIA-530/RS530 Cables 11. 3 .1 Network Cable 11. 3 .2 User Cable.
Tandberg Video on Frame Relay D11624 rev. 01 17 11. 4 Standard V.35 Cables 11. 4 .1 Network Cable 11. 4 .2 User Cable.
Tandberg Video on Frame Relay D11624 rev. 01 18 12. Appendix C: Glossary and abbreviations AVB - Automatic Variable Buffer. Buffering - This is a term used to describe a method where data is held in a queue to allow equalisation of speeds on either side.
Tandberg Video on Frame Relay D11624 rev. 01 19 - This is a Videoconferencing term, which is used to identify picture break-up. Digital video pictures are made up of 1000’s of pixels, each representing a colour on the image. In videoconferencing, pixels are grouped into blocks (the number of which is determined by the speed of the link).
Un point important après l'achat de l'appareil (ou même avant l'achat) est de lire le manuel d'utilisation. Nous devons le faire pour quelques raisons simples:
Si vous n'avez pas encore acheté TANDBERG D11624 c'est un bon moment pour vous familiariser avec les données de base sur le produit. Consulter d'abord les pages initiales du manuel d'utilisation, que vous trouverez ci-dessus. Vous devriez y trouver les données techniques les plus importants du TANDBERG D11624 - de cette manière, vous pouvez vérifier si l'équipement répond à vos besoins. Explorant les pages suivantes du manuel d'utilisation TANDBERG D11624, vous apprendrez toutes les caractéristiques du produit et des informations sur son fonctionnement. Les informations sur le TANDBERG D11624 va certainement vous aider à prendre une décision concernant l'achat.
Dans une situation où vous avez déjà le TANDBERG D11624, mais vous avez pas encore lu le manuel d'utilisation, vous devez le faire pour les raisons décrites ci-dessus,. Vous saurez alors si vous avez correctement utilisé les fonctions disponibles, et si vous avez commis des erreurs qui peuvent réduire la durée de vie du TANDBERG D11624.
Cependant, l'un des rôles les plus importants pour l'utilisateur joués par les manuels d'utilisateur est d'aider à résoudre les problèmes concernant le TANDBERG D11624. Presque toujours, vous y trouverez Troubleshooting, soit les pannes et les défaillances les plus fréquentes de l'apparei TANDBERG D11624 ainsi que les instructions sur la façon de les résoudre. Même si vous ne parvenez pas à résoudre le problème, le manuel d‘utilisation va vous montrer le chemin d'une nouvelle procédure – le contact avec le centre de service à la clientèle ou le service le plus proche.
