The Cisco Single - Wide High Density Analog Voice Service Module is designed for seamless integration with Cisco 4000 Series Integrated Services Routers (ISRs). This module features 8 RJ-21 FXS ports and 12 RJ-21 FXO ports, allowing for direct connections to public-switched telephone networks (PSTNs) and existing telephony equipment. It supports twisted pair cables for enhanced durability and signal transfer, ensuring smooth data communication. The module also includes advanced features such as Dual-Tone Multifrequency (DTMF) detection, voice compression and decompression, call progress tone generation, Voice Activity Detection (VAD), echo cancellation, and adaptive jitter buffering, making it an ideal choice for enterprises and service providers looking to optimize their voice services.