Tesis previa a la obtención del Título de Ingeniero en Electrónica y ...

)IIowing the conneclion esiahlishmmil, all Ihe lerminals will slarl lo work in Ihe following modes defined in Recomendaüon
H.22I:
- lype X: mode OF (A-law or p-Iaw):
- type Y and type Z: mode OF (A-law or u-law) audío only.
i-band procedure is aciivaied.
4.1.2 Ph.ase Bl - Mode mitiuliy.atian
,4.1.3 Phase Bl-1
sing Ihe procedures províded in Recornrnendalion H.242, l'ramed PCM audiu is iransmilled in holh direcuíons, afler
ame and mulliframe altgnmenl is gained, le.rminal capabíliiies are extihanged.
,4.1.4 Phase Bl-2 (terminal pro ce dure)
lelertnination of ihe appropriale mode lo he iransmilled. This will normally be Ihe highesl uotnmon mode (see Table 3 for
le case using a B or 2xB-channel), huí a lower compatible mode could he chosea inslead.
i Ihe case that both termináis have announced Ihe tiapahitily lo work on addiiíonal c'.haniiel(s), lerminal X iniliales Ihe
¡quesl for supplemeniary cal! sel-up. Allernaiively, ihis aclion may be suspended unül ihe user ai X has given ihe
[t-ahead, (he Y user may also control Ihe addilional channul requesls. ll is for furlher sludy.
NOTE- If ihe user ai eilher lerniina! dnes nol wish ihe cali 10 proceed lo two or more channels, even ihough his terminal
is ihís capabiliiy, he musí sel the termina! sucli ihai nnly .single-channe! capabílily is declared in phase R 1-1. In ihat cass, we should
islinguish ihe active capabilíiy, wíshed hy Ihe users, from ihe virtual capahilily of the terminal.
al
NOTES
TABLE 3/H.320
Cummon mode (default) fnr ctimmunicutiim between different types
of visual telephone.s using a B or 2xB-channeI
Xb5 Terminal ivpe
1 "b2/h:j" indícales Ihai eilher of b? or bi can be common. h? gives beiier audio, while b^
gives belier video.
2 The communiciuion minies indicaled in Ihe lable alnwe include ihe possibiliiy lo use ihe
GIF formal as weil as ihe QCIP formal. The C!F formal is used In both díreclions of
iransmission, if both lerminals indícale ibis capubüily. In a!l olher cases the QCIP formal is
used.
Each terminal may use a mínimum deeoiiahle piclure inlervaí in iis sending dirección
which makes hesl use oflhe f.apabiliiy iiulif-aled by (he olher terminal.
This table iloes nol inulude inierworking silualions belween visual lelephones and
telephone lerminals. ¡f visual lelephone lerminals are c'onnecled lo telephones, rnode a() is used
for the comrnunicaiion.
3.4,1.5 Phase Bl-3 (mude switfhing)
Both lerminals swilch lo Ihe mode Ihey have idenlii'ied in pha.se Hl-2, using Ihe prociedure of Recommendalíon H.242.
NOTE - íf ihe lerminals havc no| bolh adnpled the cununon rnode, an asymmetric communícalion may result.
Recommendatirin H.320 (03/93)
Xb
2/3
Xb5