DS-1, short for Digital Signal 1, is a digital transmission format that was used in telecommunications networks to carry voice and data traffic. It was one of the earliest standardized digital signal formats and was commonly used in North America and Japan. DS-1 is also known as T1 in North America and J1 in Japan.

Here are some key features of DS-1:

  1. Data Rate: DS-1 operates at a data rate of 1.544 Mbps (megabits per second). This data rate is achieved by multiplexing 24 voice channels (each operating at 64 kbps) and an additional 8 kbps for overhead and synchronization.
  2. Channelization: DS-1 is divided into 24 channels, where each channel can carry a voice conversation or data. These channels are known as DS0 channels.
  3. Frame Structure: DS-1 frames are organized into 193 bits, with one bit dedicated to framing and synchronization. The remaining bits are used to carry the 24 voice or data channels.
  4. Encoding: DS-1 uses a pulse code modulation (PCM) encoding scheme, where analog voice signals are sampled and quantized into digital values.
  5. Transmission: DS-1 signals are transmitted using bipolar signaling, where positive and negative voltage levels represent binary values.
  6. T1 and J1: In North America, DS-1 is commonly referred to as T1, while in Japan, it is referred to as J1. The framing and signaling conventions differ slightly between T1 and J1.
  7. Multiplexing: DS-1 signals can be multiplexed together to form higher-capacity digital signal formats like DS-3 (T3) and others.

DS-1 played a crucial role in the transition from analog to digital telecommunications and paved the way for more advanced digital transmission formats. While newer technologies and higher-capacity formats have largely replaced DS-1 in modern networks, its legacy continues to influence digital communication standards.