This video is a good guide to setting up the Kenwood TM-V71A as a simplex Echolink node.
However, when you get to the "SysOps" and "System" settings use the below settings instead.
Make sure to make the settings listed at the end on your transceiver as well!
Configure the Audio and Performance tabs.
Input Device should have the cable marked "Data Out" (pink microphone cable) plugged in
Output Device should have the cable marked "Data In" (green speaker cable) plugged in
Check "Open in Full Duplex" and "300 Hz TX High-Pass Filter"
You can lower these settings if your machine is faster. This is default, which works just fine for me. Play around and figure it out.
Configure the following settings on the "RxCtrl", "TxCtrl", and "DTMF" tabs.
Serial CTS, 0 on all timers, and select the right serial port
Select RTS, the right serial port, and check "Key PTT On Local Transmit"
Select Internal, check "Auto Mute". Function and Sequence commands are "out-of-box" in this example
This is preferential and should not affect the function of your link.
If this icon is highlighting after you release PTT, make sure your squelch source is properly configured
There are two more configurations that are needed on your physical transceiver.
Increase the audio output of your "Data Terminal" pin out. It is very low by default. It can only be configured through Kenwood's MCP-2A software. If you get reports of low audio output, this is likely the culprit.
Make sure that you select menu item 520 "SQC.SRC" as "SQL". If you do not, your echolink node will continue to transmit after you release the PTT. You can watch this happen by viewing the yellow lighting bolt (transmit) icon highlight. Your radio will not be transmitting, but the echolink software is broadcasting an empty carrier to connected nodes when this happens. This setting is likely incorrect if so.
The only way you can modify this setting is with Kenwood's MCP-2A software. Click on the "Data Terminal" option under the "Edit" menu option and set the "For EchoLink Sysop Mode" value to 6 or 7. 7 works well for me.
Menu option 520. This will properly cut off the echolink transmit function on PTT release given the above settings.