Voicepath GSM 调制解调器单个波形文件
当GSM调制解调器在语音路径中接收语音（即连续多个wave文件）时，调制解调器如何识别单个wave文件的完成？有没有任何软件可以执行此操作？
When a GSM modem is receiving voice(i.e., multiple wave files continuously) in the voice path, how will the modem able to identify the completion of a single wave file? Is there any software that could perform this?
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调制解调器实际上并不发送波形文件（在
.wav文件的意义上），因为这些文件需要一个描述文件长度的标头。相反，调制解调器会持续发送原始数据，直到呼叫结束或计算机告诉它停止。调制解调器用DLE字节后跟!表示数据结束 - 请参阅 有关语音调制解调器命令的维基百科文章 了解详细信息（以及如何在数据流中发送 DLE 字节）。至于将数据转换为 .wav 或其他可用格式：许多音频转换程序都可以做到这一点；
sox就是这样的一个命令行程序。The modem doesn't actually send wave files (in the sense of
.wavfiles), because these require a header that describes how long the file is. Instead, the modem keeps sending raw data until either the call ends or the computer tells it to stop. The modem signals the end of the data with aDLEbyte followed by a!- see the wikipedia article about voice modem commands for details of this (and for how a DLE byte is sent in the datastream).As for converting the data to .wav or another usable format: many audio conversion programs can do this;
soxis one such command-line program.GSM移动站可以支持不同的承载。根据设备功能，这包括
移动电话通常支持语音、CS数据和PS数据。 GSM 调制解调器可能仅支持 PS 数据。为了有效地利用无线信道，这些承载中的每一个都以不同的方式实现。
您可以通过数据包交换承载传输 WAV 文件，但随后它将使用 IP 技术进行传输。这需要在两个端点上都有一个应用程序来处理传输和向用户的呈现，例如播放。
语音承载提供连续的音频流，从连接呼叫开始到终止呼叫结束。 GSM 不支持语音承载上的离散音频部分。在语音承载上播放 WAV 文件是几乎所有商业设备的非标准功能。您可能需要找到支持此功能的测试设备。
如果您使用语音承载像普通电话一样播放 WAV 文件，并且想要检测播放的完成情况，您可能会检测音频中的模式（需要一种算法来计算相似性，因为您的 WAV 文件将被编码多次，并且可能混有噪声）或使用某种带外信令，某些电话支持双模式，即并行运行语音承载和 PS 承载。两者都不是微不足道的事情。
A GSM mobile station may support different bearers. Depending on device capability this includes
A mobile phone typically supports voice, CS data and PS data. A GSM modem may support PS data only. Each of these bearers are implemented differently in order to utilize the radio channel effectively.
You can transport a WAV file via an packet switched bearer, however then it will be transported using IP technology. This needs an application on both endpoints handling the transport and the presentation to the user, e.g. playout.
A voice bearer supplies a continuous audio stream, starting with connecting the call and ending with terminating the call. GSM does not support discrete portions of audio on the voice bearer. Playing a WAV file on the voice bearer is a non-standard functionality for virtually all commercial devices. You may need to find test devices supporting this.
If you use the voice bearer to play out the WAV file like a normal telephone call and want to detect completion of a playout you may detect a pattern in the audio (requires an algorithm to calculate similarity since your WAV file will be encoded several times and may be mixed with noise) or use some sort of out-of-band signalling, some phones support dual mode, i.e. running voice bearer and PS bearer in parallel. Both not trivial to do.