Different types of trunks

[stalker802]

Hi,
I always see different names in documentation: CO, FX, WATS, Tie.
But there are no simple explanation of differences between these types of trunks.
I would be very thankfull if somebody could explain me these differences.

 

[PHXAZ]

CO:Central office line ,your typical phone line.same a a POTS line.

TIE: self explanatory a line that ties 2 offices or branches together can be in another city, state or country, in essence a private path for a company to call between sites without using long distance.

WATS: Wide-Area Telecommunications Service (a telephone line;long distance service at fixed rates for fixed zones) hardly ever used now, this was s good way to save money when in the day you where charges different rates for different long distance area codes in state and out of state.


FXS and FXO are the name of ports used by Analog phone lines (also known as POTS - Plain Old Telephone Service) or phones.

FXS - Foreign eXchange Subscriber interface is the port that actually delivers the analog line to the subscriber. In other words it is the ‘plug on the wall’ that delivers a dialtone, battery current and ring voltage.

FXO - Foreign eXchange Office interface is the port that receives the analog line. It is the plug on the phone or fax machine, or the plug(s) on your analog phone system. It delivers an on-hook/off-hook indication (loop closure). Since the FXO port is attached to a device, such as a fax or phone, the device is often called the ‘FXO device’.

hopr this helps.



"Friends,Romans,Countrymen lend me your ears I come to ask for help and to give it, lets not argue on who is best or worst lets just help each other

 

[ironhorse17]

FX; foreign exchange

 

[stalker802]

Thanks.
But what would happen if I use CO trunk to make it act like Tie? I mean service provider can make its configuration to look like calls aren't going long distance on CO trunk.
Also there are DID trunks, which are also mistical for me.
If my understanding is good, FXO port can't go to wall jack, only to device?

 

[PHXAZ]

The service provider can use a CO trunk as a tie but it can only go to a predestined location. form point A to point B you cannot use it to make any other type of call, just to and from a certain location.

DID are Direct inward dial. which mean that a phone line is just a path from the central office to you. you have to programm the trunks in your system to receive the digits sent and route to the correct extension.
for example lets say you have 3 trunks. they are 3 physical paths going from the central office to you, they do not have a predetermined number associated with them.
you have 10 DIDs 777-555-6660 thru 777-555-6669
you will program your phone system so that when 6660 is sent to you on either the 3 trunks it will router to extension 1000 ans so on.

FXO and FXS are the same basically they are POTS lines


"Friends,Romans,Countrymen lend me your ears I come to ask for help and to give it, lets not argue on who is best or worst lets just help each other

 

[LkEErie]

But what would happen if I use CO trunk to make it act like Tie? I mean service provider can make its configuration to look like calls aren't going long distance on CO trunk."

In some of the older PBX's, TIE lines were called Bothway trunks. To the hardware, you can make a CO trunk look like a TIE line, but in one direction only. A TIE trunk can signal by loop seizure outbound, but it really normally uses E&M so that the trunk knows who has control. IF you use a CO trunk, you can go out, but inward isn't an option. The poor man would use DISA to receive the inward string and remove the normal 3dB pad for trunk to station calls.

With computer controlled switching, you can do just about anything you want to make the dialed digits access a route outbound. A normal TIE line goes to a point, like the branch office of a company or another city's local trunk group. With insert and remove digits, you can pretty much make a trunk behave any way you need it to. You do lose the ability to flash from the distant end and direct the call back into the originating PBX.

LkEErie