1.TDM_bus documents which help understand tdm bus

Tdm. Bus

1. 1© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
TDM bus

2. 2© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Circuit pack structure

3. 3© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
•Fit into universal slots
•TDM bus interface
–Consists of 5 custom-designed bus buffers
–Adjacent to the backplane connector (same on every
pack)
–Digital interface between TDM bus wires and circuitry
–Receive or transmit on either Bus A or Bus B
•SAKI: Sanity and Control Interface
–Receives control channel information off the TDM bus
and sends it to the angel and processor, and vice versa
–Provides all maintenance functionality and testing
control

4. 4© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
•Port controller microprocessor and RAM
–Interfaces to SPE
–Carries out instructions from the SPE for stations
–Adapts the TDM bus interface to station interface
–May actually be more than one on a pack
•NCEs: Network Control Element
–Controlled by the microprocessor
–Responsible for mapping stations on port circuits to time
slots on the TDM bus
–Performs conference and gain adjustment functions
–Has series of internal components called Network
Processing Elements, sometimes collected as a
SCOTCH
•Number of NPEs per pack varies by the pack’s functionality

5. 5© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Timeslots
•A very critical resource
•Backbone of TDM telephony
•Traffic carried through Avaya system using
timeslots
•Assigned to endpoint by the processor
•Traffic carried through the system via backplane
using timeslot
•TDM bus used for traffic movement

6. 6© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
TDM bus
•Each circuit pack connects to the bus by connecting to the
backplane
–In a slot
–In a carrier
•TDM is part of the backplane: wires run across the back of
the carriers
•Inter-carrier cables connect carriers
–So circuit packs in one carrier can communicate with circuit packs
in another
•One TDM bus structure (redundant bus) per port network
–Consists of Bus A and Bus B
–But function as a single bus

7. 7© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
•Sample voice 8000 times per
second @ 8 bits per sample
–2.048 MHz bandwidth chosen
–Divide by 8000 samples
–Yields 256 time slots per 125
microsec. (or one sample
every half microsecond)
–8 parallel paths = 16.384Mbps
–Clock synchronizes access
•Network Control function controls
access via SPE
•One pair of bus per port network,
Bus A and B
•Shared resource

8. 8© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
•Runs internally in each PN
–Carried on backplane of each carrier
–Cable connects each carrier in series
–Terminator at each end
–Operates at 2.048Mbps
•Two 8-bit parallel busses: Bus A and Bus B
–Normally active simultaneously
•Carry signals between port circuits and
–Processor
–Port circuits
•Port circuits place digitized voice and data signals on the
bus

9. 9© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
•Two bus give redundancy if one fails
–Port network remains functional, if at reduced capacity
–Improves system reliability
•Two bus lowers the speed required of each bus
•Appears as one 512-slot bus
–Bus A is usually 0-255
–Bus B is 256-511
•Normally the tone bus as well

10. 10© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Will conversation take place?
Write access
Talk Path
Listen Path

11. 11© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Conversation requires 2 slots
Write access
Write access
Talk Path
Talk Path

12. 12© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Conference
•How many timeslots
required to conference all 4
station

13. 13© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
Conference
•Each phones gets one
timeslot for writing
•All other phones can read
from that timeslot

14. 14© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
TDM bus slot assignments

15. 15© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
CCMS slots
•10 slots are reserved for the CCMS, but only one
Bus (A is the default) is active using 5 slots
•Maintenance monitors the Busses to determine
which should be active
–Informs rest of processor which bus to use
–AA in each PN tells the Angels in that PN which Bus to
listen to for CCMS messages

16. 16© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
TDM tone bus
•Tones are carried on one
bus
•Usually carried on Bus B
–When Bus B is down,
then they are carried on
Bus A
–They would be in slots 5-
21 on A
•Bus with tones is known as
Tone Bus
•Tones are used to generate
touch tone Dual Tone
Multiple Frequency signals
Analog ring is separate lead on backplane
at different voltage and frequency
261 697 Hz
262 770 Hz
263 852 Hz
264 941Hz
265 1209 Hz
266 1336 Hz
267 1477 Hz
268 1637 Hz
269 Dial Tone
270 Reorder Tone
271 Intercept Tone
272 Busy Tone
273 Digital Ring*
274 Call Waiting
275 2025 Hz
256 Internal Control
257Internal Control
258 Internal Control
259 Internal Control
260 Internal Control

17. 17© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
How many 2-way conversation
possible??
How many time slots are there in a port network?
___
How many are for CCMS oneachbus? ___
total=___
How many are used for tone generation per PN?
____
How many others are reserved on each bus? ___
total=___
How many are left? _____

18. 18© 2008 Avaya Inc. All rights reserved. Use pursuant to Avaya policy.
How many 2-way conversation
possible??
How many time slots are there in a port network?
__512_
How many are for CCMS oneachbus? 5___
total=10___
How many are used for tone generation per PN?
__16__
How many others are reserved on each bus? __1_
total=__2_
How many are left? _242____
____