VoIP Nodes on WB6NDJ
Information about the ORCA Repeater
This presentation was given at
the March 2018 ORCA meeting
AllStar Link: 47154
Repeater 442.40+ PL 77.0
VoIP is short for Voice over Internet Protocol. Using the same techniques to transmit telephone calls, the audio from the radio is converted into data packets and sent over the internet. VoIP Nodes is a developing project with a goal to share hardware and software resources for IRLP, AllStar Link and EchoLink systems. Software is installed and being tested that allows one WB6NDJ Raspberry Pi (RasPi) Linux computer system to connect to AllStarLink and EchoLink network nodes and a second RasPi to connect to IRLP network nodes.
For more information on each system please visit the following websites:
The software installed on the WB6NDJ IRLP node is referred to as the "VoIP Nodes" project.
What this software does or does not do:
Does allow you to cross connect one IRLP node to multiple AllStarLink and EchoLink nodes together. (This is new!)
Does provide the WB6NDJ IRLP node access to available EchoLink clients and conferences.
Does allow multiple simultaneous EchoLink clients to connect to the WB6NDJ-R EchoLink node number 270352.
Does provide the WB6NDJ IRLP node access to available AllStar Link nodes.
Does allow multiple simultaneous AllStar Link nodes to connect to the WB6NDJ-R AllStar node number 47154.
Does provide registered AllStar AROs to link the WB6NDJ-R AllStar node number 47154 via the internet or telephone.
Does not allow multiple simultaneous IRLP clients, so please avoid using IRLP for the weekly net sign-in.
The following DTMF code list controls the operation of the two WB6NDJ RasPi's. Start by transmitting DTMF letter D to ensure that subsequent DTMF codes will bypass the controller and go to the RasPi's.
DTMF Code Description
D A 0 - Announce node status, e.g. link clear, connected, etc.
D A 1 - Announce local node date and time.
D A 33 - Announce local weather for Metro Oakland International Airport.
D A 34 - Announce weather alert for East Bay Oakland Hills.
D A 35 - Announce weather forecast for East Bay Oakland Hills.
D XXXX - Connect to IRLP node/reflector - four digit number.
D 73 - Disconnect from IRLP node/reflector.
D * 3 3 XXXXX - Connect to Echolink node/conference number.
D * 1 3 XXXXX - Disconnect from Echolink node/conference number.
D * 3 XXXXX - Connect to AllStarLink node.
D * 1 XXXXX - Disconnect from AllStarLink node.
(note: AllStarLink nodes do not begin with the number 3. That number is reserved for routing to Echolink)
GENERAL IRLP USER GUIDELINES
IRLP has some restrictions that are not shared by EchoLink and AllStarLink. In particular, IRLP can connect to only one node at a time. However, it has a conference mode. So many of these guidelines apply to all VoIP linking systems. As with any new technology, it does take some time to adapt to operating procedures that differ from conventional FM repeater use. This work in progress can serve as a guideline for those wishing to use their local IRLP enabled repeater node.
COMMON IRLP MODES
There are two connection modes for an IRLP connection. Direct one-to-one or, one-to-many via a Reflector. Direct connect is just like it sounds where repeater (node) "A" connects directly to node "B". With this type of link, the two nodes are interconnected and no other IRLP connections are possible. While repeaters "A" and "B" are connected, anyone attempting to connect with either node will be told by a recording that - "The node you are calling is currently connected to callsign" however all local traffic on each repeater will be heard on the other repeater as well. While Direct Connect is preferred for a city-to-city chat, the most common type of connection in use today is via Reflector. A reflector is a Linux computer that is not connected to any radio but rather sits on lots of Internet bandwidth capable of allowing many repeaters to be inter-connected together by streaming the received audio back to all other connected stations. Each reflector has 9 subchannels allowing up to 10 separate virtual reflectors to operate. These are identified by the last digit. For example - 9250 is the main channel with 9251, 9252 9253 etc being virtual reflectors with identical capability as the main channel. You can always check which stations are connected to the reflectors main and sub-channels by visiting http://status.irlp.net and looking for nodes connected to individual nodes or reflectors.
REFLECTOR / CONFERENCE / ECHOLINK / ALLSTARLINK USE
With multiple nodes connected the first thing we must all remember is to leave a gap between transmissions. Having said that this is a good time to list the three main rules when connected to a reflector:
Rule 1: Pause
Rule 2: Pause
Rule 3: Pause
Due to the slight increase in delays created by multiple Tone Squelch radios in the links between the repeater and VoIP link radio, a slight change in our normal operating procedures is required with VoIP. By leaving a pause between transmissions it allows users on other nodes a chance to check in. Allows other nodes time to send touch-tone commands to drop their node. The most important guideline to remember is leaving a pause after pressing the PTT button as well as between transmissions.
Avoid local traffic while connected to an IRLP reflector. By its nature, the reflector has a large footprint and a wide audience, therefore if local users would like to have a discussion, they should disconnect from the reflector.
Along the same line, if two stations become engaged in an extended dialog involving only themselves, then I would recommend they both move off the IRLP reflector and make a direct node to node connection, freeing up the reflector for others. If more than two nodes are involved, then moving to one of the lesser-used reflectors or making multiple connections using EchoLink and AllStarLink might be an alternative, especially if one of the stations can check the web site for an available reflector. In the future, moving to one of the available sub-channels will become an option.
To make a contact, it is preferable to say "This is KB6XYZ is anyone available for a contact?" as opposed to "KB6XYZ Listening" ...silence for 2 minutes, followed by a disconnect. It IS acceptable to talk about the weather or anything else that is geographically significant. But like anything else, within reason. A station in Indiana that says to a Colorado op, "Hey I heard that you have a mountain out there" will probably cause eyes to roll worldwide. In general, long-winded, channel-consuming conversations should be avoided. Remember there are usually a dozen or two connected systems, with perhaps hundreds of users that might like a chance to use the system.
A few other Reflector and multiple connected VoIP nodes operational guidelines:
Listen first. When connecting to the main channel on a Reflector, odds are that you are dropping into an existing conversation. This might also happen using EchoLink or AllStarLink.
Wait for at least 15 seconds to make sure you are not interrupting an existing QSO before calling.
Pause between transmissions. Many nodes are connected using simplex links, therefore the only time it is possible for them to disconnect is between transmissions. Be sure to pause AT LEAST 5 seconds between transmissions.
Key your transmitter and wait before speaking. There are propagation delays across the Internet, as well as delays caused by sub-audible tone decoders and other devices that cause a delay before the audio path is cut through. If you speak immediately upon PTT, the beginning of your transmission will not be heard.
MAKING A DIRECT VOIP CONNECTION
First of all, listen to your local machine for at least 15-30 seconds before transmitting and then ask if the repeater is currently in use. Assuming all is clear, identify your self and announce your intention to make a VoIP call. Example: "KB6XYZ connecting to IRLP node" then enter the code for the node and release your PTT. Your local repeater should come up with a carrier as it waits for the connection to be authenticated. This can take a few seconds of dead-air so don't be concerned. When the connection is confirmed, the voice ID of the destination node will be transmitted back to you as well as your nodes voice ID to the other repeater. NOTE: If your node is already connected to another node or reflector, a greeting will play saying - "your node is currently connected to... the ID of the connection") In this case confirm if anyone desires the connection to remain up before dropping by using the disconnect code. Once connected and after hearing the confirming voice ID, wait at least 15 seconds before transmitting as the repeater may be in use, and your entry may have occurred between transmissions. The voice ID of your node is longer than the voice ID of their node, and the connection is not made until the ID is fully played. Their computer may be slower and hence take longer to process the connection than yours. Press and hold the microphone PTT for a second and then announce your presence and your intention such as you are calling someone specifically or just looking for a QSO with another ham in that city. If no response is heard, announce your call and your intent to drop the link and then touch-tone in the disconnect code. Not a good idea to transmit touch-tone commands without first giving your callsign. Not only is this courteous it is a regulatory issue in some countries who may be connected to the reflector. Some nodes are configured so you cannot connect to them if that repeater is active. In this case, you will receive the message "The node you are calling is being used locally" If you receive this message wait 5 or 10 minutes and then try again. If you stay connected to a node and there is no activity on your repeater for 4 minutes, the connection will time out and automatically disconnect with a voice ID disconnect message on both nodes.
CONNECTING TO THE REFLECTOR
As above, listen to your local machine for local use and then announce your intention for the Reflector before keying the connect command. When you hear the confirmation ID always WAIT at least 15 seconds before transmitting as you are most likely now connected with many repeaters and a QSO could be in progress. If after 15 seconds you hear nothing, identify yourself and indicate you are listening to the Reflector from "City and, State ". With the worldwide IRLP activity, your local repeater now has worldwide coverage thus the suggestion to better detail your QTH. Don't be in a hurry to hear someone come back to you. You may have to do a bit of pleading from time-to-time to dislodge someone from whatever they are currently involved with. By default, if you stay connected to a reflector with and there is no activity on your repeater for 20 minutes, the connection will time out and automatically disconnect. However many node owners set this period for a long period so it is not unusual for repeaters with minimal traffic to stay connected to the Reflector for extended periods of time. When or if the node times out from a Reflector connection a standard time-out greeting will precede the timeout saying, "Activity time out ... Reflector xxxx, link off" If you hear or wish to engage in a prolonged rag-chew on your local repeater (long discussion of a local nature) out of courtesy to other node listeners drop the reflector.
From time-to-time, you may receive error messages when attempting to connect with a node or reflector. The most common ones are:
"The node you are calling is not responding, please try again later"
This is caused by a loss of Internet connectivity to one end of the call attempt.
"BEEP Error - The call attempt has timed out, the connection has been lost"
This error occurs when a node is OFF-LINE. Some nodes such as in the UK use dial-up connections and then, only for short periods. Also, there may be temporary net or node problems.
"The Connection Has Been Lost"
If the Internet connection drops, this error message will be heard.
REFLECTOR DO'S and DON'TS
To conclude there are a few do's and don'ts
DO pause between transmissions to let others in or others to enter DTMF command.
DO identify before sending DTMF command tones.
DO hold your microphone PTT for about 1 second before talking to allow all systems time to activate.
DO NOT rag-chew on your local repeater while connected to the reflector.
DO pause for 15 seconds or when entering the reflector before talking.
DO NOT start or plan a Net without pre-authorization from the reflector owner.