Double Recording Time gives you the option of recording on a standard cassette at either normal speed or half the normal speed, for extended recording or dictation sessions
Voice Operated Recording activates the recorder only when audible sound is present, conserving tape and eliminating soundless passages
Long Battery Life
Playback Speed Control lets you adjust playing speed as much as +30% or 
Battery Indicator with Alert LED confirms battery operation and alerts you of low battery power with flashing LED
Microphone Jack allows connection of an external microphone
Clear Voice™ Recording System enhances voice quality during recording and playback, for greater clarity
One Touch Recording for simplified, quick play/record operation
Cue and Review provides sound during fast Forward and Rewind modes to help find specific passages
3V 
Monaural Earphone Jack provide sound in both ears when using with an optional stereo headset
Hinged Battery Lid helps prevent accidental loss when changing batteries
TCM-400DV specifications
The Sony TCM-400DV is a compact and portable cassette tape recorder that reflects the artistry and innovation typical of Sony's dedication to audio technology. Designed primarily for voice recording, this device offers a range of features that cater to users looking for simplicity coupled with functionality.One of the notable features of the TCM-400DV is its lightweight construction, making it easy to carry around for recording on the go. The design prioritizes user-friendliness, featuring a straightforward control layout that allows users to operate the device effortlessly. With large buttons and an intuitive arrangement, both novice and experienced users can quickly navigate its functions.
The TCM-400DV is equipped with a built-in microphone that delivers clear audio quality, making it ideal for interviews, lectures, and personal notes. For those who require a higher-quality recording, the device also accommodates external microphones which provides added versatility. The ability to connect an external mic allows users to achieve better sound quality depending on their recording environment, making it suitable for various applications.
In terms of technology, the TCM-400DV utilizes a high fidelity system, ensuring that recordings capture the nuances of sound effectively. The automatic level control feature is especially beneficial, as it adjusts the recording level in real-time to prevent distortion and maintain audio clarity, even during fluctuations in volume.
The playback functionality of the TCM-400DV is equally impressive. It includes a built-in speaker that produces clear sound, enabling users to listen to their recordings without needing additional equipment. Additionally, the device provides options for fast-forwarding and rewinding, allowing for quick navigation through tapes.
A standout characteristic of the TCM-400DV is its battery efficiency. It operates on standard AA batteries, giving users the freedom to record for extended periods without needing to recharge or replace batteries frequently. This is particularly advantageous for field recordings or events where access to power might be limited.
Overall, the Sony TCM-400DV is a versatile cassette recorder that combines ease of use with high-quality audio features. It remains a valuable tool for anyone looking to capture sound in a straightforward and reliable manner, reflecting the enduring appeal of cassette technology in an ever-evolving digital landscape. Whether for professional applications or personal use, the TCM-400DV continues to hold its ground as a dependable audio recording solution.