- •Question for the exam in subject Switching systems and information distribution. 2016-2017 a.Y. Оглавление
- •Principles of national telephone network construction in Ukraine. Numbering in national telephone network.
- •Figure 1.4 - National numbering format.
- •1.2 National Numbering Plane
- •Principles of zonal telephone network construction in Ukraine. Numbering in zonal telephone network.
- •Principles of urban telephone network construction (utn). Example of utn with five digit numbering construction. Example of analogue-digital utn construction.
- •Switching method classification. Channel, message and packet switching. Switching method comparison.
- •Switching method classification. Channel switching technology. Features, advantages and disadvantages.
- •Switching method classification. Message and packet switching technologies. Features, advantages and disadvantages.
- •Digital switching fields. Construction and operation principles of space switching unit (ssu) with parameters 2×4×6 built upon мх.
- •Digital switching fields. Construction and operation principles of space switching unit (ssu) with parameters 2×4×6 built upon dмх.
- •Digital switching fields. Construction and operation principles of time switching unit (tsu) with parameters 1×8×8. Control modes in tsu.
- •Il ol g c o u n t e r cm cell- cm cell- cm cell- cm cell- Controller
- •Dss «Kvant-e». Subscriber access subsystem. Analogue subscriber lines including.
- •Line access subsystem of a dss
- •Dss «Kvant-e». Analogue customer unit borscht function.
- •Dss «Kvant-e». Subscriber access subsystem. Slu-128 scheme. Short description of main elements.
- •Figure 2.2 – Narrowband access subscriber module of Kvant-e
- •Dss «Kvant-e». Subscriber access subsystem. Algorithm of outgoing call in slu-128.
- •2.2 Algorithm of connection set up
- •Step 1. Dial tone sending
- •Step 2. Pulse dialing
- •Step 5. The controller of sm-b operates sm-b equipment in order to establish connection
- •Step 7. Answer of subscriber b
- •Dss «Kvant-e». Subscriber access subsystem. Algorithm of incoming call in slu-128.
- •Dss «Kvant-e». Signalling subsystem. Innersystem signalling, issc packet structure.
- •Architecture of dss si-2000. Parameters and short characteristics of modules mlc and mca
- •Architecture of si-2000 dss
- •Multiservice subscriber access networks based on dslam (ban). Review of wired multiservice access technologies.
- •2) Broadband access node an-bb (ban, hBan, miniBan, microBan)
- •Example of tasks.
Step 5. The controller of sm-b operates sm-b equipment in order to establish connection
The ISSC signalling packet travels through SSU of SM-B and via the bus reaches the controller of subscriber module of subscriber B.
The controller receives the signalling packet and checks whether a phone of subscriber B is on-hook (not busy).
If phone B can not receive the call then the controller of the SM-B generates a signalling packet about the seized state of subscriber’s B phone. The controller of the SM-B sends this packet to the CD of SCU with the help of
ISSC. Then the CD of SCU sends the packet towards the controller of SMA in order to inform it about inaccessibility of the phone B. The controller of SM-A performs switching in order to provide the busy tone for subscriber A. The busy tone comes from the DGTS.
If phone B is idle then the controller of the SM-B sends a packet towards the CD of SCU in order to inform it about the idle state of SL-B. Eventually this packet reaches the controller of SM-A.
Step 6. Diagnostic procedures and further connection setup
The TU connects to the voice wires via contacts of K1 and K2 relays in order to test the presents of unexpected voltage over the wires of subscriber line of subscriber B.
The controller of the SM-B operates contacts of relays in order to connect a ring signal generator (Ring) to the wires of subscriber line of subscriber B. Ring generator provides 25 Hz AC ring signal towards the subscriber B. Subscriber B hears the phone ringing.
The controller of the SM-B performs switching in order to connect DGTS to the voice transmission path in order to send the ring back tone towards subscriber A.
Step 7. Answer of subscriber b
Subscriber B picks up his handset which results in closure of subscriber loop. A scan point of the CU-B identifies this closure.
If the closure of subscriber loop occurs then the controller of SM-B switches off both the ringing generator and digital generator of tone signals.
The controller generates an ISSC signalling packet in order to inform the CD of SCU about the answer of subscriber B. The CD of SCU transmits the same packet towards subscriber module of subscriber A.
Step 8. Conversation between the subscribers
– After performing ISSC signalling exchange, all the controllers (CS-A, CSB and CD) create voice transmission path between phones and supervise the voice transmission path. Microphones of phone A and phone B require power supply. Appropriate customer units provide power supply for the microphones.
Step 9. Phone of subscriber A is in the “on-hook” state
Subscriber A returns his handset on the phone, which results in “on-hook” state (breaking of the subscriber loop).
The scan point of CU-A identifies this “on-hook” state. The CU-A informs (through PLM) the controller of SM-A about the “on-hook” state of subscriber A.
The controller generates a packet about the “on-hook” state of subscriber A and sends it to the CD of SCU.
All the controllers perform disconnection of the voice transmission path.
Step 10. Sending the busy tone towards the “off-hook” subscriber
The controller of SM-B connects the DGTS to the subscriber line of the subscriber B in order to provide the busy tone towards subscriber B.
In order to do so the controller connects TC-2 of T-7 (where the DGTS is assigned to) to the TC-0 of T-4. After the switching the digital signal (busy tone) goes to the CU-B. The CU-B converts the digital signal to the analogue acoustic signal and subscriber B hears the busy tone.
After hearing the busy tone subscriber B returns his handset back to the phone. The controller of SM-B performs final disconnection (returns DGTS to initial state).