/mcp© 2019 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 7 of 13 ● FXS-E (extended loops) support: FXS ports on the new modules support FXS-E with the following details: ◦ Higher loop current (35 mA) to accommodate specialty phones ◦ Longer loop length for loops with 26 AWG wire, up to 11,000 feet (3400 meters) ◦ Higher ringing voltage (65 Vrms, no load) ◦ The SM-X-72FXS module supports two FXS-E modes: ● Mode 1 (default): First 16 ports are FXS-E enabled, with the remaining 56 ports as regular FXS. ● Mode 2: First 56 ports are FXS-E enabled, with the remaining 16 ports disabled. Note: Switching between the modes requires reload of the ISR chassis. Table 2 summarizes the supported FXO failover bypass feature in each service module. ● FXO failover bypass ports: A failover bypass port, also called a failover trunk bypass, provides a way to use designated analog phone ports to make phone calls through the PSTN during a power outage. Table 3. Feature and port comparison Part number Number of FXS ports Number of FXO ports FXO failover bypass ports FXS-E enabled ports SM-X-8FXS/12FXO 8 12 8 8 SM-X-16FXS/2FXO 16 2 2 16 SM-X-24FXS/4FXO 24 4 4 16 SM-X-72FXS 72 – – Mode 1: 16 (FXS-E)/ 56 (FXS) Mode 2: 56 (FXS-E)/16 (disabled) Analog and digital voice NIM (Network Interface Module) support on VG450 VG450 allows to mix and match the high density analog voice modules (Single wide and double wide module slots) along with FXS/FXO Network Interface Modules (NIM) on the chassis to obtain optimal density for FXS and FXO ports in a single chassis. Following are valid hardware combination options for high density analog voice modules in service module slot for VG450 bundles. VG450-144FXS/K9 ● Two SM-X-72FXS modules on VG450 for 144FXS Ports (top and bottom DW slots). VG450-72FXS/K ● One SM-X-72FXS module (bottom DW slot) with at least one single-wide high density analog voice module in top slot (mandatory). Max two single-wide high density analog voice service module in top slot. ● Only double wide high density module (SM-X-72FXS) supported in bottom slot. VG450/K9 ● Chassis only without any modules or NIMs.