Regarding PABX Systems

How large is the facility?

it is 13.82*2 = 27.64 MW plant. It is a surface power house

sks

How many people work there?

I am not so sure about how many people work there........few people will sit in the powerhouse control room, few on the damsite control room, and few on office building.

How much telephone traffic will there be?

telephone traffic will be high as people constantly need to communicate within the powerhouse and outside the powerhouse.

sks

How many outside lines will there be?

There shall be at least 3 outside lines one for PH Control room, one for Damsite control room, and one for office building.

sks

What sort of systems support three outside lines in terms of the numbers of extensions?

i am not so sure, but at least three dedicated lines we need to communicate with the central load dispatch system.........all the other telephone can be used with an extension '0' to communicate outside the powerhouse. within the powerhouse, they do not need to have a code like '0' - they can simply dial for eg. three digit number to communicate.

sks

What are the budget contraints?

let us make it economic and efficient.

sks

Is rental an option?

well, by rental i think you mean - renting leased lines? Otherwise, we intend to procure it. we are consultant only.

sks

What makes of systems are available locally?

NEC PABX 4-IN 8-OUT System [SL1000 : IP4WW-1632M-A KSU] - are they japanese?
Regards,sks

See. The answer was there all along. It's only a case of asking questions. _{<unsubscribes>}

these seems to be: Main System Unit | Expandable upto 64-IN 128-OUT, are they?
sks

what is 4 in 8 out system?

sks

PWSlack, but my question is still unanswered...what is no of extensions....is it one main line, and the branches from it are called no of extensions?

sks

Telephone systems are generally sized for the average usage between extensions and lines. An extension is the actual cct that connects to the telephone, whilst the lines are the circuits you rent from the telephone company. The ratio of extensions to lines depends on the nature of the business but anything from 3:1 to 50:1 can be adequate, this is where the telecoms designer comes in.

To size the system you start with the no and type of telephones required. So for a plant i would expect perhaps the number of telephones to be greater than the number of people, e.g. telephones are often located in un-manned locations such as sub-stations or remote plant rooms etc. Once the total number has been designed and you have decided whether to use digital phones or POTS (plain ordinary analogue phones) you can then decide on the type of system - analogue, digital or hybrid.

You then need to understand the usage of the "trunk side of the exchange, i.e. how many exchange lines are needed to carry the traffic that is external to the site, this again is a telecoms engineeing job.

Next is backup, if using an analogue system and you use analogue lines you can have a simple bypass relay that enables basic outgoing calls if the system fails. Battery backup is often used to keep the system going if there is a local power failure.

I used to design phone systems a decade or so ago for BT so just giving you a flavour of what is required. Hope this helps

P & S, but we have manned stations here in Nepal.

regards,

sks

OK, same applies

P & S, but in a hydropower of my study, they preferred hybrid system.......i.e. certain lines analog and certain lines digital........isn't this more complex and expensive? Also, I studied that anything for eg. 'using 9 or 0 to dial outside' is always digital. Is it like this? Also, how to understand PABX of type: NEC PABX 3-IN 8-OUT System [Topaz : IP2AP-924M KSU]

From Standard data:

Manufacturer: Alcatel

Type: Alcatel 4400

Number of extensions equipped: 88 (72 analog, and 16 digital)

Number of trunk lines (equipped/expandable): 3 to NTC, 3 to LDC, 8 to public network.....

From this data, i could not figure out what is 8 to public network.........?? and what is 3 to NTC? (Is it Nepal Telecommunication Corporation for Nepal.......but this is a public utility for operating a public network in Nepal)..

regards,

sks

Hybrids are OK and allow for in-expensive phones to be located in "works" environments along with bells, lights and whistles if its noisy. BTW they are extensions not lines, lines are on the trunk side. Using 9 or 0 to dial an outside line is normal for all systems and is set by the administrator of the system as in some cases you do not wish some phones to be able to dial an outside line as it generally costs money to make that call.

The trunk (public network) lines can come in different flavours. Off the top of my head LDC is probably loop disconnect (standard analogue trunk) no idea what NTC is but some trunk lines are digital based upon Euro ISDN but again not done one in Nepal. It really depends whats available in that location and then you equip the system with the number and type of trunks you need. LDC and ISDN trunks will be on different cards (usually) so you either order the trunk cards for the lines you are getting from telephone company.