Tong quan ve tong dai

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Tng quan v tng I

Tng quan v tng iPHn I / Gii thiu chung v tng i

I/ Tng qut v tng i

Tng i in t k thut s xut hin vo cui thp k 60, th h tng i ny ny s dng k thut phn knh theo thi gian , gia tng dung lng v s dng k thut mi . T u thp k 70 tr li y , cc hng chuyn nghin cu v sn xut tng i cho ra i cc th h tng i c kh nng chuyn mch vi cc dung lng khc nhau t tng i ni ht nh nht cho n cc tng i chuyn mch qu giang ln nht hay nh : in thoi, ISDN ( Mng lin kt a dch v ), in thoi di ng , mng t nhn o v tt c cc ng dng ca mng tr tu .

Hin nay cc h thng tng i c dung lng va v ln c th u ni vo cc mng :

Mng in thoi tng t hoc s

Mng my tnh

Mng bo hiu s 7

Mng chuyn mch gi

Mng thng tin di ng

Mng dch v h tr

Mng thng tin bng rng

Mng khai thc v bo dng

Cc h thng tng i c dung lng nh nh c cp n sau ( KX-TA308,KX-TA616) khng hon ton u ni c vi cc loi mng nh h thng tng i c dung lng ln , n ch dng cho cc cng xung , nh my , x nghip , c quan tn dng ti a cc trung k vo . Ngoi ra tng i loi ny cn tit kim mt khi lng khng nh v ti chnh cho ngi s dng n . V vy tnh n nay hu nh khng mt c quan , x nghip , nh my, cng xng no m khng dng tng i loi ny.y l u im ca tng i panasonic loi nh . Cn nhc im ca n l khng u ni c vi cc mng khc cung cp cc dch v c lit k trn .

II/ Cc dch v tng i cung cp

1) Dch v x l cuc gi

X l cc cuc in thoi vo/ ra mng chuyn mch quc gia v quc t. N cn truyn s liu gia cc thu bao ISDN m n qun l , cng nh truyn s liu vo ra mng chuyn mch gi .

Cc cuc gi ni ht: T nhn, cng cng.

Cc cuc gi trong vng : ra /vo chuyn tip.

Cc cuc gi quc gia : ra /vo chuyn tip

Cc cuc gi quc t : t ng , bn t ng, gi ra , gi vo.

Cc cuc gi nhn cng : gi ra , gi vo

Cc cuc gi n cc dch v c bit

Cc cuc gi a kim:

2) Cc dch v cung cp cho thu bao

i vi cc thu bao tng t , cung cp cc dch v nhm h tr vic thc hin ni kt cc cuc gi c tin hnh thun li v hiu qu trong c mt s dch v ng ch . Cung cp cc ng dy c bit cho thu bao nh : ng dy nng , ng dy ch gi ra , gi vo , nhn dang thu bao quy ph , quay s vn tt cn i vi cc thu bao s ( digital) cng cung cp y nh thu bao tng t , bn cnh n cn cung cp cc dch v thu bao c bit nh dch v mng , dch v t xa v dch v ph tr.

3) u ni operator

Tt c cc h thng tng i tu thuc vo h thng c dung lng ln hay nh m ph hp vi module theo h thng ( ph thuc vo nh sn xut ) .

Module c th s dng qun l mt vi h thng ni ht n vi trm h thng ni ht hoc xa trong mt vng hoc nhiu vng khc nhau.

Hot ng vi tin cy cao , phn mm ca h thng c phn cp , c th thay i d dng ti bt k thi im no m n cp n nhiu chc nng: cc nhm lu lng ho, ho n tnh ton o lng ti v o lng .

4) Chc nng vn hnh v bo dng:

Qun tr v gim st s c, qun tr theo khiu ni , t ng o kim ng thu bao, trung k , hin th cnh bo, xc nh v tr li , thng k cc cuc gi , vn hnh thit b u cui thng minh .

Gim st vn hnh : Thu bao nhm , thm dch v, thit b thu bao , lnh trao i , phin dch to tuyn , tnh cc , bo hiu s 7.

Qun tr cc : tnh cc tp trung , tnh cc ti ch , lp ho n chi tit , thoi cng cng , cc vng theo thi gian.

Qun tr s hot ng ca tng i : o lng ( lu lng cc ng thu bao , xung tnh cc , phin dch , m thi gian gi ).

Bo mt bng m kho (password) cho trm vn hnh v ngi iu hnh trnh xm nhp khng c php

III /. H thng bo hiu v iu khin trong tng i

1) H thng iu khin trong tng i

Mi chc nng ca tng i c lp trnh ho v np sn. Cu trc iu khin ca n c xy dng trn 2 phng thc. X l n hay a x l ( X l tp trung hay phn tn ).

X l n ( X l tp trung )

c p dng cho tng i c nh c vi chc n vi trm s, vi phng thc ny c c im: li v kinh t nhng hn ch v tc ph hp cho tng i dung lng nh. Dng nhiu lnh gn can thip vo vi x l n gin. loi ny c cu trc nh l mt h thng vi x l hon chnh. S s l n trong chuyn mch

Ngi ta np h s cc thu bao ti RAM, cc thuc tnh ca th bao v cc trng thi u c th lp trnh k2 bo bng vic thng qua giao tip I/O. C th thm nhp bng TERMINAL hay my tnh.

2) H thng bo hiu

Khi nim

thng tin c thng sut trong mng th phi c thng tin nghip v. Thng tin ny c phc v cho thng tin tht do phi c h thng bo hiu. K thut bo hiu c chia lm 2: ni dung bo hiu v phng thc truyn bo hiu.

Ni dung bo hiu l th tc phi tri qua 2 i tng lin lc c vi nhau.

Phng thc truyn bo hiu c th coi h thng bo hiu l mt h thng thng tin in hoc coi nh mt h thng truyn s liu.

Bo hiu c chia lm 2 loi sau:

Nu xt ni ti mt chuyn mch th bo hiu chia lm 2 loi:

Bo hiu ng dy (bo hiu trng thi)

Bo hiu thanh ghi (bo hiu chn s hay bo hiu a ch)

Nu cn c theo h thng truyn dn bo hiu c chia lm 2 loi:

Bo hiu thu bao

Bo hiu trung k

Bo hiu thu bao v bo hiu trung k

Bo hiu thu bao

L vic trao i thng tin bao hiu gia tng i v thu bao.

Ni dung bo hiu gm cc trng thi sau:

Xt hng thu bao ti tng i: bo hiu ng dy gm cc trng thi nhc t my, bo hiu thanh ghi l cc bo hiu v cc s c quay.

Nu xt t tng i ti thu bao bo hiu gm cc thng tin a ra t tng i: Tone mi quay s, tone bn, hi m chung v cc thng bo c bit khc.

Bo hiu trung k

L thng tin c trao i trn ng trung k gia cc tng i vi nhau. Do c nhiu loi trung k nn ni v phng thc truyn bo hiu c khc nhau nhng nhn chung th ni dung v phng thc truyn bo hiu cng gm:

Ni dung bao hiu:

Bo hiu ng dy (bo hiu trng thi): l cc iu khin kt ni, iu khin ngt, trng thi cm gii to.

Bo hiu thanh ghi (bo hiu a ch): truyn cc a ch gm s ch gi, s b gi.

Phng thc truyn: Tu thuc vo loi trung k v dch v tng i cho php m c cc phng thc truyn bo hiu khc nhau. C th truyn xuyn sut hay tng chng, trong bng hay ngoi bng, trong khe thi gian hay ngoi khe thi gian, bo hiu tn s hay a tn.

Bo hiu xuyn sut: (end to end)

Bo hiu c truyn t tng i u cho n tng i cui, cc tng i lm nhim v chuyn tip khng x l bo hiu. V d nh mt thu bao ca tng i A gi mt thu bao ca tng i M th a ch thu bao ca tng i M gm m vng, m thu bao c truyn ton b n tng i M. Tng i M c nhim v phn tch s v phc v cuc gi.

Bo hiu tng chng : ( Link by Link )

Bo hiu c phn tch ti cc nt chuyn tip . Mt a ch ca thu bao b gi s c phn tch ti cc tng i chuyn tip m a ch ca thu bao s c ct dn qua tng chng

V d : mt thu bao b gi c a ch ABCM xxx th cc m u a ch ABCM s c loi b qua tng nt A, B, C, M. Ti tng i cui ch phn tch s thu bao. Phng thc ny thc cht l vic trao i s liu gia cc b x l bo hiu ca cc tng i vi nhau.

Bo hiu trong bng, ngoi bng :

S dng trn ng thoi Analog c di tn 0,3 3,4 KHz

Ngoi bng : thoi v bo hiu khng nh hng ln nhau. Nhng phi hn ch v ni dung v cht lng.

Trong bng: chuyn ni dung ln, tc cao, nh hng nhiu n cht lng thoi. V vy lm th no phn bit gia tn hiu thoi v tn hiu bo hiu ngi ta s dng t hp 2 tn s ca su tn s thnh 15 t hp gi l bo hiu R2 MFC. C su tn s cho hng i v su tn s cho hng v to thnh 10 t hp cho 10 s v 5 t dnh cho iu khin.

Bo hiu trong khe, ngoi khe:

H 24 knh ca M s dng tt c cc bit th 8 ca cc khe thi gian trong khung 6 v khung 10 trong mt a khung bo hiu. Bao hiu trong khung su thuc nhm A, trong khung 12 thuc nhm B. y l bo hiu trong khe.

H 32 knh cho Chu u s dng khe 16 (TS16) ca cc khung t F0 F15 truyn bo hiu, mi mt khe 16 phi ghp 2 bo hiu cho hng i v v. Mi bo hiu l mt t m 4 bit a, b, c, d. 4 bit bn tri bo hiu cho knh thoi t 1 n 15, bn phi cho knh t 17 n 31. y l bo hiu ngoi knh.

IV/. ng trung k

Cc tng i thng khng hot ng c lp thnh cc mng ring m n c cc ng thng tin kt ni vi nhau gi l cc ng trung k. Cc ng trung k ny c th l ng in thoi trung k CO, c th l trung k lung E1/PCM. Hoc cc ng trung k E&M 2 dy hoc 4 dy.

1) Trung k CO

nh ngha: L ng kt ni thng tin gia cc tng i s dng cc i dy tn hiu in thoi.

Nu nhn t tng i gc th PBX l thu bao ca tng i gc, nu nhn t tng i PBX th ng tn hiu ny l mt trung k.

Tu thuc tng loi PBX c kh nng dch v khc nhau m trung k CO c th thm nhp vo, ra trc tip hay phi chuyn tip qua bn in thoi vin.

Bo hiu:

Bo hiu trng thi: Trng thi nhc hoc t my c th l chp mch vng (loop Start) hoc chp t (ground start).

Bo hiu a ch: c th bng xung (rotary) hoc tone tu thuc vo s nhn bit dch v ca tng i gc.

1.1) Trung k E&M (Trung k Tie)

nh ngha: L ng kt ni thng tin gia cc chuyn mch trong cc ng tn hiu thoi v bo hiu truyn ti trn cc ng dy c nh ngha sn. C 2 loi trung k E&M:

Trung k E&M 2 dy: Gm 2 dy thoi, mt dy E&M v mt dy M.

Trung k E&M 4 dy: Gm 4 dy thoi thu v pht, 1 dy E v 1 dy M.

ng trung k ny c th kt ni trc tip gia cc tng i ph thuc vo c li cho php hoc c th kt ni viba qua thit b r knh MUX.

Th tc bo hiu kt ni:

Trung k E&M c th s dng ch gi a ch bng tone khi ny cc chn E&M ch lm nhim v bo hiu chim trung k. Bo hiu a ch c truyn trn i dy pht ca ng thoi.

1.2) Trung k lung

nh ngha: L ng kt ni thng tin gia hai tng i m thng tin truyn trn di dng s.

ng trung k s c hai loi: Trung k s E1 v trung k s T1.

Trung k s 2,048MBps: (trung k s E1)

Thng tin c truyn di dng s v c ng thnh cc khung thng tin vi di mi khung Tf = 125 (s. Mi khung c chia thnh 32 khe thi gian (Time slot) t Ts0 n Ts31, mi mt khe thi gian ghp mt t m 8 bit, di mt khe thi ny l 3,9 (s. Tc mt bit ny l 448 ns.

Cu trc thng tin:

Ts0: dnh cho ng b khung

Ts16: dnh cho bo hiu

Ts1 Ts15: Cc knh t 1 15

Ts17 Ts31: Cc knh cn li.

C 16 khung thng tin to thnh mt a khung. Tt c khe thi gian th 16 (Ts16) ca cc khung t F0 n F15 s dng lm bo hiu. V c 30 thu bao u truyn bo hiu nh nhau nn mi Ts16 phi ghp hai bo hiu cho hai thu bao. Mi bo hiu l mt t m 4bit a,b,c,d. 4 bit bn tri dng cho cc knh t 1- 15,4 bit bn phi dng cho cc knh cn li.

Trung k 1,544 Mb (Trung k s T1)

Thng tin c ng thnh cc khung t