Page Type: SYMPTOM
The 'No Audio Port' error occurs when the Rangecast software is in communication with the radio scanner (over the com/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 causes include a problem with the Windows audio or USB system, or a loose connection on an audio cable or to a sound card within the interface box. (Note this error does not mean that the audio port does not exist, but that the audio port cannot be located by software. This could be due to the port being missing, or an audio cable being disconnected, or a volume level problem resulting in no audio reaching the PC.)
DIFFERENCES IN RANGECAST HARDWARE
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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.
OLD Rangecast installations used a USB "Black 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.
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1. Check Windows volume setting for each audio input. Windows provides a master volume setting for each audio input. If the volume is set too low, then the Rangecast software will not be able to clearly hear the scanner when automatically detecting the scanner's audio port. This can result in an error message (NO AUDIO PORT) indicating that the scanner's audio cannot be detected. Therefore, a good first step is to check the Windows volume setting for each audio input, to ensure that none of the inputs is set too low. See the instructions for Low Volume
[FAQ-1223] Error message: LOW VOLUME (Code 46)The LOW VOLUME warning means that, when the scanner is set to a test condition where it receives static, the observed audio level is less than 40% of full volume. If the input levels are too low, the audio recordings may have lower quality. Also, the Rangecast software may not be able to reliably detect that the audio port is associated with a particular scanner, rendering the scanner either consistently or intermittently inoperative.
[FAQ-1084] Power cycle the USB systemOn occasion, some element of the USB system (in either the PC or external hardware) may freeze (probably in firmware), and become unresponsive until it is power cycled. Simply turning a PC off/on may not clear the issue, since many PCs keep minimal power applied to some circuits. To ensure a clean power cycle of the USB hardware, physically disconnect the PC power cable for at least 30 seconds (with Windows safely shut down.)
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.
SYMPTOM