Cisco medium-density Analog Voice Gateway provide enterprises, managed services providers, and service
providers the ability to directly connect public-switched telephone networks (PSTNs) and existing telephony
equipment to Cisco 4000 Series Integrated Services Routers. These FXS and FXO ports provide Dual-Tone
Multifrequency (DTMF) detection, voice compression and decompression, call progress tone generation,
Voice Activity Detection (VAD), echo cancellation, and adaptive jitter buffering. Cisco VG400 Voice Gateway
is a medium-density analog voice gateway. It is an intermediate path that enables TDM to IP transition.
The Cisco VG400 Voice Gateway supports the following interfaces:
• Two RJ45 Gigabit Ethernet (GE) ports
• One RJ45 Console Port
• One USB 2.0 Port
• LED for System, GE Port, and Console Port Status
• Features and Benefits of Cisco VG400 Voice Gateway, on page 1
• Cisco VG400 Voice Gateway Chassis, on page 3
• LED Indicators, on page 4
• Slot, Bay, and Ports, on page 5
• Technical and Compliance Specifications, on page 7
• Platform and Software Requirements, on page 9
Features and Benefits of Cisco VG400 Voice Gateway
Cisco VG400 Voice Gateway provides VoIP connectivity to analog devices, such as analog desk phones,
analog conference room phones, fax machines, and modems. Cisco 400 Voice Gateway provides several
improvements from the previous high-density analog and digital extension modules (EVMs), in the following
ways:
• On-board Digital Signal Processor (DSP)—The FXO and FXS ports contain an onboard DSP and
don’t require the router to have a dedicated packet voice DSP module (PVDM) on the motherboard. The
DSP on the voice module is necessary for the voice features. It also provides for echo cancellation of up
to 128-ms echo-tail length for demanding network conditions.
• 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)
In addition to these features, Cisco 400 Voice Gateway also supports the following features:
Introduction to Cisco VG400 Voice Gateway
• Higher ringing voltage (65 Vrms, no load)
• 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.
• Caller line ID
• G.711, G.729a, and G.726
• G722, iLBC, GSMAMR-NB, and Internet Speech Audio Codec (iSAC)
• Fax detection, pass-through, and relay (T.38)
• Modem pass-through
• DTMF detection
• Echo cancellation
• Voice activity detection
• Comfort noise generation
• Real-Time Control Protocol (RTCP)
• Acoustic shock protection
• Real-Time Transport Protocol (RTP)
• RFC 4733 Digit Relay
• Noise reduction is on the roadmap
The FXS features include:
• Support for either FXS or DID functionality
• Message-Waiting Indicator (MWI)
• Cable detection: GR909 line test
• The FXO features include:
• Support for both ground-start and loop-start modes
• Support for FXO CAMA signaling type
• Call Detail Record (CDR) information
• Support for interworking with Cisco Unified Communications Manager (Skinny Client Control Protocol
[SCCP]), H.323, Session Initiation Protocol (SIP), and Media Gateway Control Protocol (MGCP) 0.1
• Cable detection
• Overload protection
Analog Phone Connectivity
Cisco 400 Voice Gateway are ideal for analog phone deployments ranging from centralized to sparsely
concentrated or distributed topologies. Cisco 400 Voice Gateway offer many supplementary analog calling
features, depending on the call control and signaling type used. All supplementary analog features are supported
through the FXS and FXO ports. The analog interface on Cisco 400 Voice Gateway also supports Feature
Access Codes (FACs) for invoking supplementary services.
Fax and Modem Connectivity
FXS ports on Cisco 450 Voice Gateway support fax machines and modems. When using fax machines, the
gateways support T.38 fax relay and fax pass-through. T.38 fax relay technologies allow transfer of faxes
across the network with high reliability using less bandwidth than a voice call. All modems can be connected
to the Cisco VG Series Gateways and are transferred over the network using modem pass-through.
Protocols Supported
The voice gateways support the following protocols:
• SCCP
• H.323v4
• MGCP
• SIP
• Real-Time Transport Protocol (RTP)
• Secure Real-Time Transport Protocol (SRTP)
• Trivial File Transfer Protocol (TFTP)
• HTTP server
• Simple Network Management Protocol (SNMP)
• Telnet
• Dynamic Host Configuration Protocol (DHCP)
• DNS
• Cisco Unified Communications Manager or Cisco Unified Communications Manager Express redundancy
support using Hot Standby Router Protocol (HSRP)
• Call survivability: MGCP failover to an H.323 connection to the Survivable Remote Site Telephony
(SRST) router
• T.38 fax relay and modem pass-through
• Codec support: G.711, G.729. G.729a will be used if the gateway does not support G729 annex b
• RADIUS and TACACS+ for Telnet and authorization
Protocols Supported
Cisco VG400 Voice Gateway Chassis
The following figures show the front and back panels of the Cisco VG400 Voice Gateway Chassis:
Figure 1: Front panel of the Cisco VG400 Voice Gateway
BIOS/ROMMON has
completed booting, and
system is at the
ROMMON prompt or the
booting platform software
Compact flash/eUSB flash
is present and is currently
being accessed.
Note Do not remove the
flash device while the
system is powered on.
All the temperature
sensors in the system are
within the acceptable
range
One or more temperature
sensors in the system are
outside the acceptable
range
Slot, Bay, and Ports
The FXO port is used to connect to PBX or key systems, or to provide off-premises connections to the PSTN.
It supports battery reversal detection and caller ID. The FXO port is also used to connect to analog Centralized
Automatic Message Accounting (CAMA) trunks to provide dedicated E-911 service (only in North America).
The FXS port is used to connect analog phones, modems, fax machines, and speaker phones to an enterprise
IP voice system, to use them as extensions to your Cisco or third-party IP call-control system. Having these
Off
Fan statusFAN
Amber
Blinking Amber
Temperature is not being
monitored
All the fans are operatingGreen
One of the fans has
stopped working
Two or more fans have
stopped working, or the
fan tray has been removed
devices tightly integrated with the IP-based phone system is advantageous for increased manageability,
scalability, and cost-effectiveness. The Direct Inward Dialing (DID) port is used to provide off-premises DID
connection from the central office. It serves only incoming calls from the PSTN. The Caller ID feature is not
supported in DID mode.
The following table provides information about Cisco 400 Voice Gateway SKU:
Table 2: Cisco 400 Voice Gateway FXS-E/DID, REN, Failed-over Port Support
Introduction to Cisco VG400 Voice Gateway
Maximum Number or RENsMaximum Number of FXS-E PortsInterface
102VG400-2FXS/2FXO
124VG400-4FXS/4FXO
126VG400-6FXS/6FXO
Table 3: Slot, bay, and port information for Cisco VG400 FXS Port
PortBaySlotInterface
0-1102FXS/2FXO
0/1/0-1
0-3104FXS/4FXO
0/1/0-3
Number of Failed-over PortsRJ-11
Connectors
2FXS: 1x2
FXO: 1x2
4FXS: 1x4
FXO: 1x4
6FXS: 1x2 1x4
FXO: 1x2 1x4
—FXS: 1x4 1x4168VG400-8FXS
0-5106FXS/6FXO
0/1/0-5
0-7108FXS
Table 4: Slot, bay, and port information for Cisco VG400 FXO Port
Short-loop-length port:
3000 ft (900 m) with 26
AWG, 5500 ft (1700 m)
with 24
AWGLong-loop-length
port: 11,000 ft (3400 m)
with 26 AWG, 18,000 ft
(5500 m) with 24 AWG
Short-loop-length port:
3000 ft (900 m) with 26
AWG, 5500 ft (1700 m)
with 24
AWGLong-loop-length
port: 11,000 ft (3400 m)
with 26 AWG, 18,000 ft
(5500 m) with 24 AWG
Short-loop-length port:
3000 ft (900 m) with 26
AWG, 5500 ft (1700 m)
with 24
AWGLong-loop-length
port: 11,000 ft (3400 m)
with 26 AWG, 18,000 ft
(5500 m) with 24 AWG
The following table details the compliance specifications of Cisco VG400 Voice Gateway.
Short-loop-length port:
3000 ft (900 m) with 26
AWG, 5500 ft (1700 m)
with 24
AWGLong-loop-length
port: 11,000 ft (3400 m)
with 26 AWG, 18,000 ft
(5500 m) with 24 AWG
Category 3 and Category 5Category 3 and Category 5Category 3 and Category 5Category 3 and Category 5Cables
Cisco 400 Voice Gateway is supported on IOS XE Release16.10.1. The ports provide gateway services for
Cisco Unified Communications using Cisco Unified Communications Manager or Cisco Unified
Communications Manager Express. The following list provides information about the software version that
is compatible with the FXO and FXS ports:.
• CUCM: 12.5.1, 12.0.1su2 and 12.0.1 (with device pack)
• IOS XE: Version 16.10.1 and later
Configuration Methods
After Cisco 400 Voice Gateway is operational, use the procedures in Cisco 400 Voice Gateway Software
Configuration Guide to configure the specific services and functions or to make changes to an existing
configuration.
There are multiple methods for configuring Cisco 400 Voice Gateways:
Platform and Software Requirements
• System configuration dialog
• Configuration mode: Cisco IOS software CLI
• Setup command facility: Remote configuration through a LAN
• SNMP-based application: CiscoView or HP OpenView
• HTTP-based configuration server: Provides access to the CLI from a web browser