Rangecast FAQ
[FAQ-1014] Error Message: NO AUDIO PORT (Code 26)

Page Type: SYMPTOM


Sender was unable to find the audio line from its assigned scanner.


The Rangecast software is in communication with the radio scanner (over the data port), but is unable to find an audio input to the PC that appears to have this scanner's audio output. Therefore, Rangecast cannot capture the audio content from transmissions received on this scanner. The most common cause is a problem with the audio cable or USB system.


POSSIBLE CAUSES and repair options:

(1) AUDIO LEVEL SETTING TOO LOW - The audio channel may be working but the level is set abnormally low in the Windows sound panel. (Try setting all sound channels to about 50, which should be a safe guess in most installations.)

(2) AUDIO CARD FAILURE - The USB audio sound card may be locked up or defective. (Try disconnect and reconnect. If that does not work, try different interface hardware)

(3) AUDIO CARD DRIVER PROBLEMS - The driver software in the PC may stop working properly. (Try a PC reboot)

(4) WINDOWS SOUND FREEZE - In this condition all Senders will report NO AUDIO PORT, because all sound lines are frozen in the PC. It may be triggered by attempting to access a bad sound card. The SOUND FREEZE condition can be cleared by PC reboot.

The following two causes apply only if the older 4-scanner USB interface box is used:

(4) UNPLUGGED AUDIO CABLE - A audio cable may be partially or completely unplugged. (Check audio cable.)

(5) AUDIO CABLE IN WRONG SCANNER JACK - The audio cable must plug into the GREEN jack on the rear scanner panel. (Check.)


Note - The problems and solutions differ depending on what Rangecast interface hardware is being used. THIS TECH NOTE IS TEMPORARY and general. Separate notes should be written later for each hardware scenario.

Differences in Rangecast hardware:

OLD Rangecast installations used a USB box to interface up to 4 scanners to the PC. The box provides an enclosure to protect 8 interconnections between USB cables, audio sound cards, and audio cables. Any of these can become disconnected due to vibration or stress and will cause malfunctions. Opening the box and checking that everything is connected is sometimes necessary.

NEW Rangecast installations use individual Rangecast RCX interface units mounted directly on the back of each scanner. The connections to the radio are secure. A single USB cable provides audio and data connections to the PC. Disconnecting that cable breaks all communications, causing a RADIO MISSING message instead of a NO AUDIO PORT message.


Here is how a Sender finds its correct audio line.

A typical feedsite may have four scanners. Each has an audio connection to the PC. The audio connection may a standard audio cable to an USB audio sound card. In newer installations an "RCX" box with an internal USB sound chip is mounted on the back of a scanner, plugged directly into the scanners audio jack. The PC receives the audio over a USB connection. In either case, a Sender commands its assigned scanner to play alternating NOISE and QUIET periods and listens to each line to find the matching pattern. When detected, it begins normal Rangecast service.

(1) Note that the Sender must be able to "hear" audio from the scanner for this to be possible. If it cannot hear the noise/quiet pattern, then it cannot find its audio audio line. In that case the Sender will display a NO AUDIO PORT message and turn an indicator red. It will try again periodically.

(2) Note also that a NO AUDIO PORT message confirms that the Sender is in data communication with its scanner. This usefully confirms a number of good things; that the Sender is working, that the proper scanner is present and responding normally, that the data connection works. The issue is specifically an audio problem.



Rangecast FAQ - ID 1014 - last updated 02 August 2017     Images shown - [block]