1. Telephone System
By : Warsun Najib

2. 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

3. 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),

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

5. Side Tone

6. Dialing System
DTMF (Dual tone multi frequency)
Rotary Switch

7. Dual Tone Multi-frequency1 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]

8. 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)

9. Dialing : Rotary Switch7 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

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

11. 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

12. 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

13. 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

14. Illustration of Call Switching

15. 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.

16. 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

17. 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

18. Voice Signaling

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

20. 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

21. Numbering System
Open System
Close System

22. 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

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