What are FXS & FXO?

What are FXS & FXO?

FXS — Foreign Exchange Station

FXO — Foreign Exchange Office

An FXS device initiates and sends ringing voltage. FXS sends the voltage to an FXO device, which receives it.

The phone receiving the call is the last FXO device in the chain, and when it receives voltage from an FXS device, the phone will ring.

Connect the outside line to an FXO port on your Asterisk server to receive voltage from the outside lines.

Connect the phones to FXS ports on your Asterisk server. When the FXO module in your Asterisk Server receives the voltage, it will then generate voltage using the FXS module and send it to your analog phone.

Hint: Remember the “to”… FXS = FX(to)Station and FXO = FX(to)Office.
With “to” representing the direction taken by the signal.

Dynamic Paths

Just like other living things there are good and bad times for dynamic paths that are taken.

One can opt to be static yet knowing dynamic paths will move you.

What does this mean to those that work in the area of emergency response?

Be flexible with the methods that are used, yet maintain the basic standards that allow a incident operation to be conducted safely. Standards which remain static can be used as a basis for operation integrity and also represent a road map to a successful mission.

Standard Operation Procedures provide the static portion for operational planning yet they should also be dynamic so that when new methods are presented they can be placed into the Standard Operation Procedures as soon as possible.

Every situation, every incident is different, thus the need for being dynamic in operational style. At times incidents will take place that are not amongst the normal operational situations. This indeed is one of the times that we need to be dynamic in readiness and response.

Flexibility is a key ingredient to readiness and the all hazard approach to emergency response and planning.

As a organization which path are you opting for: static or dynamic flexibility?

Digital Frontiers

In the 1800s there was the frontier of West. Today we have digital frontiers to explore. The digital frontiers may not always be digital voice or data that appears within this new frontier.

Some may remember the days of 1200 baud packet that was quite popular in the 1990s. This technology is now present in APRS, with even a hint of low-speed data showing up within the VHF and UHF bands via D-STAR enabled radios as well as telemetry.

For those that have radios such as the Icom ID-1 it is possible to have 100kbps data from the Internet available in your vehicle. In order to do this a base station with a ID-1 or a D-STAR 1.2GHz data repeater is required.

Most of us have some form of a wireless network in our home or business that operates via the 802.11 standards. Did you know that this same equipment can be used in Amateur Radio with higher RF power and higher gain antennas? Within Amateur Radio this technology is known as High Speed Multi Media or HSMM. The primary bands for HSMM are 2400, 3300 and 5800 MHz. The 902 MHz band can also be used for high speed data. One of the key advantages to HSMM is in its nature of being able to take a off-the-shelf wireless network adapter and access point add a higher gain antenna to them, and for longer range RF amplifiers can be added under FCC Part 97 rules.

Imagine having access to high speed video, IP-phone and Data Connectivity in your vehicle,or during special events and emergency incidents being able to provide data, video and voice to the agencies served. As well as providing last mile coverage into a disaster area.

Did we mention telephone service? With the development of Internet telephone services as well as telephone servers such as Asterisk which provide flexible interoperability between PSTN, Internet Phone and Radio dial tone can be presented along with the last mile capabilities of High Speed Multi Media create a resource that can be highly beneficial to the community and the nation.

What is next in the Digital Frontiers? As it was in the 1800s with the migration West the same is occurring with the digital migration. With networks such as Asterisk the migration is made easier as analog and digital technology is made one. On the Internet you can find more information about Asterisk and HSMM at http://asteriskradio.net and http://hsmm.info


In development news we picked up five more nodes for connectivity to the Allstar Link Network.   These five nodes will be used in the Communications Transportable Systems (CoTS).  Also they are beneficial in understanding the proper procedures for setting up multiple node servers both for the Asterisk Radio Network – ARN and Asterisk Amateur Radio Network – AARN.

Already have CoTS-1 configured and interfaced into the PBX, still need to configure up some HSMM wireless links that can be used for point-to-point and point-to-multiple point applications.

Remote Base

Remote Base:

What is the function?

What will it be used for?

How will it connect to other stations?

What is the function:

A Remote Base provides a method in which locations outside the normal range of a Base Station or Repeater can be accessed. Thus providing additional communications coverage area.

What will it be used for:

Provide additional communications coverage area; also can be used to augment communications resources in emergency situations and special events.

How will it connect to other stations:

Depending on the complexity of the Remote Base (and the amount of funds available) the ideal situation would be to have a combination of RF and Internet backhaul capabilities. If Internet access is available this would be the ideal method for connectivity. Once again if funds are available use of Satellite Internet services would provide some additional remote accessibility.

When using RF backhaul capabilities there are number of methods that can prove to be beneficial. When possible consider VHF Links and for full-duplex A VHF / UHF combination. We cannot forget about the flexibility of HSMM on 2.4, 3.3, 5.8 GHz and even 902 MHz has some promising potential.

Can HF be considered a viable extension of the Remote Base Link? Depends on the mission objective. Looking back to some of the applications in the past couple of years where HF Remote Base Links have been used as a method to receive emergency traffic from distant locations out of normal range of EOC there may be some practical usage for HF.

The way the Amateur Radio licensing is set up it is rather tough to test a station in a non-emergency setting. Especially for those holding a Technician Class license. There are some that have taken the test for the General and Extra class license and passed the test yet don’t have a clue about the technology that they were tested on. It appears that some don’t really care about the technology just the fact that they can now “talk voice on HF.” In some instances voice on HF will not be the best approach for getting the necessary information from those that have it to those that need it.

Okay back to the Remote Base chatter …

So what do we need to create a Remote Base?

What do we need to create a Remote Base:

Determine the type of terrain in which the Remote Base will operate;

is it urban, rural, forested, hilly, mountains, etc.

What resources are available;

  • Internet; Dial-up, Broadband, HSMM, Satellite;
  • RF Equipment – HF, VHF, UHF, Microwave;
  • Power – Grid, Solar, Wind, Battery, Generator
  • Antenna Structure – Building, Tower, Mast;

What is the distance that needs to be covered between the Remote Base and Base / Repeater Site:

Will the distance require additional enhancements via extenders, cross-band repeaters, etc:

Once the above information is available we can start working on creating the actual Remote Base

Digital Integration to PSTN

A new digital project is coming up that will provide a method to push digital radio traffic to SIP / IAX2 phones as well as PSTN. Testing is in progress now, more details coming soon.