Understanding Spoken Message Systems

The question asks to identify a communication system with specific functions: it must digitize a spoken message, transmit it over a network, and allow the receiver to retrieve it later.

Analyzing Communication Options

Let's examine each option to see how well it matches the described system:

1. Instant Message Analysis

Instant messaging (IM) systems are primarily used for real-time, text-based conversations. While some modern IM apps allow voice or video calls, their core function isn't digitizing a single spoken message, transmitting it as a stored item, and waiting for retrieval. They focus on live or near-live text exchange.

2. E-mail Analysis

E-mail is a versatile system for sending electronic messages. It can transmit text, files, and even audio recordings as attachments. However, the primary function isn't specifically designed around digitizing a simple spoken message and storing it for retrieval in the way a dedicated voice system does. Sending an audio file via e-mail requires separate recording and attachment steps, unlike the integrated process described.

3. Fax Machine Analysis

A fax machine transmits scanned documents (images) over telephone lines. It converts the visual information on a page into an electronic signal for transmission. It does not handle spoken messages or audio digitization.

4. Voicemail Analysis

Voicemail systems are precisely designed for the task described. When a user leaves a message:

• The system digitizes the spoken message using the phone's microphone and hardware.
• It then transmits this digital audio data over the phone or IP network.
• The message is stored on a server.
• The intended recipient can later access the network and retrieve their stored messages at their convenience.

This option perfectly matches all the criteria mentioned in the question.

Conclusion on Spoken Message System

Based on the analysis, the system that digitizes a spoken message, transmits it over the network, and stores it for later retrieval is Voicemail.