Telephone System By : Warsun Najib

Telepon System Concept Telephone network is often called as PSTN (Public Switch Telephone Network) Telephone Device Central Office (CO) suatu istilah untuk menggambarkan pusat jaringan telepon (dalam suatu kota). Tugasnya menyediakan daya untuk telepon, me-routing panggilan, merekam tagihan telepon, dsb. Trunk (E1) Link/kabel between CO to other CO Local Loop Pasangan kabel telepon yang terhubung antara central office dan pesawat telepon rumah (kantor). Switch Perangkat yang me-route komunikasi ke bagian (tempat) yang lain. Pada awalnya, switch terbuat dari banyak switch-switch mekanik Saat ini, mayoritas switch adalah elektronis, bahkan digital. Digital switches lebih reliable, dan menawarkan banyak keuntungan Distribution Network MDF Rumah Kabel

Telephone Set Hibrid Pemisah mic dengan speaker Penekan nada samping Dialer Mic Speaker Bell Hook Switch 1 2 Standby : Hoook switch is on position 1, Idc from CO does not come, Ringing signal (ac) can activate Bell Busy : Switch is off-hook (hook-switvh on position 2),

Telephone : Off-Hook / Busy dial I DC H D bicara lawan IDC bicara saudara I dc I sendiri

Side Tone

Dialing System DTMF (Dual tone multi frequency) Rotary Switch

Dual Tone Multi-frequency 1 2 3 4 5 6 7 8 9 # * Baris 1 [697 Hz] Baris 2[770 Hz] Baris 3[852 Hz] Baris 4[941 Hz] Kolom 1 [1209 Hz] Kolom 2 [1336 Hz] Kolom 3 [1477 Hz]

DTMF i(t) Digit ‘1’ Digit ‘6’ space T T t Periode T > 100 ms depend on how fast finger push the button (normally 250 ms)

Dialing : Rotary Switch 7 6 5 4 3 2 1 8 9 v1 v 2 I ‘1’ one stop pulse ‘2’ two stop pulse ‘3’ three stop pulse … ‘0’ ten stop pulse

Rotary switch dialing system T :100 ms ≥ 4T ‘3’ ‘2' i(t) t space Dial a number Off-hook

Subscriber link signal (Link Voltage) 100 50 -50 -100 -150 Bell, ringing voltage Dialing pulse voice Off-hook On-hook Incoming Outgoing 1-2 V ingoing 0,5-1 V I:16-20 mA, 6-8 V 48 V Δv: 48 V ΔI: 18 mA 20 Hz, 90 Vrms, 2 s on, 3 s off

Switching Element trunk SLIC Switching Device Pengisyaratan Controller Central Office register Switching Device Controller trunk SLIC Pengisyaratan To/from other CO Controller can be : Sentralized Distributed at signaling and switcing Device SLIC : Subscriber Line Interface Circuit

Switching System Step By Step, Each digit activates directly one switching-level, except the last 2 digit usually connected to 2-dimension switch 3054 3 5 4 Call Finder Switch level 1 Switch level 2 Switch level 3 Switch level 4

Illustration of Call Switching

Common Control Each digit of dialed number is first stored in a register at CO, then if the destination number is not busy, call is routed to the phone.

Switching Process of Telephone Call Caller lift handset / off hook CO find the available link Get a link No Yes CO send dial-tone to caller Caller dial the destination number

CO make switching process Is dialed number free (not busy) ? yes no CO send busy tone to caller phone CO send: Ringing signal to dialed phone Ringing tone to caller phone (tuut – tuut…..) Called phone Off hook Call drop No yes Call success

Voice Signaling

Private Branch eXchange CO Common Subscriber ... m ext-link PBX 90XXXX 2201 2202 1302 ... n main link Operator

PBX is categorized: PMBX private manual branch exchange Both intern and extern call is handled by an operator PABX-private automatic branch exchange Intern call is automatic Extern call Automatic if the device has DID (direct inward dialing) Via operator If device does not have DID If n >1 (link between co-pbx) User call via one number if PABX has hunting system User can call via n different number if PABX doesn’t have hunting system. Advantage of PBX Cost Probability of success call

Numbering System Open System Close System

Network from CO to Subscriber Primary network LE - MDF CCP CCP MDF 2000 pairs CCP 50 pairs DP:10 pairs DP DP PBX DP Secondary network MDF,CCP,DP are in a form of cable switching terminal

Network Between LE LE Toll Central Regional yk1 yk2 yk3 One local area