The high-density analog voice/fax network modules provide enterprises, managed service providers and service providers the ability to directly connect the PSTN and legacy telephony equipment to Cisco 2600, 2800, 3600, 3700, and 3800 Series access routers. This provides immediate multiservice advantages, such as telephony toll bypass, new packet telephony applications, and full gateway integration within a Cisco AVVID (Architecture for Voice Video and Integrated Data) IP telephony architecture.
Figure 1. NM-HDA Network Module with 12 FXS Ports and 4 FXO Ports
The voice/fax modules for the Cisco 26/28/36/37/3800 Series multiservice access routers enable packet voice technologies including voice over IP (VoIP), voice over Frame Relay (VoFR) and voice over ATM (VoATM). Cisco voice solutions provide the means for integrating both voice and data within a single network allowing users to take advantage of services, such as toll-bypass, without sacrificing voice quality. Cisco IOS® Software also incorporates built-in quality-of-service (QoS) features along with standards-based (FRF.11 and FRF.12) encapsulation and fragmentation, providing efficient direct transport of voice and fax over IP, Frame Relay, and ATM networks. These Cisco IOS solutions enable time-sensitive voice traffic to be moved across even low-bandwidth WAN connections with the priority and quality that voice/fax demands. Transporting voice over IP networks continues to provide transport flexibility since IP can be routed across a multitude of WAN technologies (leased lines, Frame Relay, and ISDN) along with providing direct connectivity to the desktop.
These high-density analog voice/fax network modules also provide the gateway to Cisco AVVID for calls to and from the PSTN and legacy telephony equipment (including PBXs, analog telephones, fax machines, and key systems). Users can deploy networks which leverage investments in existing legacy telephony equipment while also deploying and integrating IP telephony immediately or in the future. These network modules enable users to operate at any point on the voice, video, and data integrated infrastructure spectrum while incrementally adding connections to both legacy telephony and IP telephony on these networks.
The analog voice/fax network modules install into Cisco 2600, 2800, 3600, 3700 and 3800 Series network module slots and provide standard analog interfaces to the telephony equipment and the PSTN. The high-density analog voice/fax network modules (NM-HDA) serve up to 16 analog ports, or four times the number of ports supported by the low-density analog voice/fax network module (NM-2V).
Specifically, the NM-HDA contains four FXS ports on the base board and room for two expansion modules (EM). The two types of EM, daughter cards that plug into the NM-HDA, available are an eight port FXS and a four port FXO. Using different combinations of ports on the base board and two EMs, an NM-HDA can service up to 12 FXS + 4 FXO ports, or 4 FXS + 8 FXO ports. (Note: A configuration using two 8-port FXS EMs is not supported.)
Each NM-HDA module includes enough digital signal processing (DSP) resources on-board to service eight voice calls using high-complexity codecs or 16 voice calls using medium-complexity codecs (see list of codecs supported in Table 5). In addition, the NM-HDA provides a connector for a daughter module, called DSP-HDA-16, which can serve an additional 8 high-complexity or 16 medium-complexity calls. Table 1 lists all the modules that are available for NM-HDA.
A Cisco 2600 and 2800 Series router can house one NM-HDA module, a Cisco 3660 router can house up to six network module while a Cisco 3700 Series router can house up to four network modules. Table 2 shows the number of NMs supported by each platform.
Table 1. Cisco NM-HDA Module Descriptions
Module
Description
NM-HDA-4FXS
High-density analog voice/fax network module with four FXS ports
EM-HDA-8FXS
Eight-port FXS voice/fax expansion module
EM-HDA-4FXO
Four-port FXO voice/fax expansion module
EM2-HDA-4FXO
Enhanced four-port FXO voice/fax expansion module
DSP-HDA-16
16-channel DSP module for NM-HDA
Table 2. Maximum Network Modules Allowed per Platform
Platform
Maximum Number of NM-HDAs Allowed
2600/2600XM/2691
1
2811/2821/2851
1
3640/A
3
3660
6
3725
2
3745
4
3825
2
3845
4
Table 3. Cisco NM-HDA Module Functions
Module
Application
NM-HDA-4FXS
The base board is always required for any configuration of NM-HDA. It comes with four built-in FXS ports. Use an FXS port to connect directly to analog phones, fax machines, and key systems.
EM-HDA-8FXS
Use an FXS port to connect directly to analog phones, fax machines, and key systems.
EM-HDA-4FXO
Use to provide off-premise analog connections to the central office for loop length (the length of wire between the FXO module and the central office) up to 8,000 ft. in U.S., Canada, and other countries (configurable). Includes support for battery polarity reversal detection and Caller ID. Also supports "power failover" on one port.
EM2-HDA-4FXO
Supports the same density and features as the EM-HDA-4FXO, but provides enhanced features. These include longer loop length support of greater than 8k feet and improved performance against poor line conditions when used in groundstart signaling mode.
DSP-HDA-16
Use to provide additional DSP resources for NM-HDA when more than eight high-complexity calls are required.
Table 4. Features and Benefits Summary
Feature
Benefit
Voice/Fax over IP
Voice and fax traffic are transport independent because IP traffic at Layer 3 can travel over any Layer 1 or Layer 2 media, including ISDN, leased lines, serial connections, Frame Relay, Ethernet, Token Ring, and Asynchronous Transfer Mode (ATM).
Voice/Fax over Frame Relay
Applications requiring voice and fax traffic to be routed directly over Frame Relay networks will take advantage of FRF.11 and FRF.12 VoFR and fragmentation standards. This solution also uses features found only in Cisco IOS Software for maintaining voice quality.
Voice over ATM
Transport voice directly over ATM networks using AAL2 or AAL5 encapsulation. Leverages existing ATM networks as a direct transport method for voice. VoIP can also be transported over ATM.
Connection Trunk
Creates a tie-line replacement structure while only consuming bandwidth during a call (digital-to-digital, digital-to-analog, or analog-to-analog capabilities).
LVBO (Local Voice Busy-Out)
Automatically busy out any desired voice trunk line to a PBX or PSTN when a direct WAN or LAN connection to the router is down. Also, busy out a far end trunk connection when configured for Connection Trunk.
Caller ID Support
Per-port configurable caller ID to phones connected to analog FXS voice ports using per call unblocking if desired. Also provide caller ID over analog FXO voice interfaces. Interoperates with analog phones, PSTNs, PBXs, H.323 terminals (that is, Microsoft Netmeeting), Cisco CallManager, and IP phones.
Call Admission Control using RTR
Uses Response Time Reporter (RTR) to determine latency, delay and jitter and provide real-time ICPIF calculations before establishing a call across an IP infrastructure. RTR packets emulate voice packets receiving the same priority as voice throughout the entire network. A superior method to data and ping packets for determining congestion levels.
Voice and Fax over Same Port
Ports can be used for both voice and fax traffic--no dedicated ports are required.
Works with Existing Phones, Faxes, PBXs, and Key Systems
No user retraining is required.
H.323 v3/v4 Compatibility
The Cisco voice/fax modules are interoperable with numerous emerging voice and videoconferencing applications, such as Microsoft NetMeeting, Intel Internet Phone, LAN-based IP telephony equipment, and Cisco CallManager.
High-Performance DSP Architecture
The Cisco voice/fax modules offer extremely low latency, which is essential for high-quality voice and fax traffic; the DSP architecture also enables all critical functions to be handled in software, which allows for simple code updates, scalability, and new features.
ITU Standard Codecs such as G.729, G.729a/b, and G.711
These are standards-based compression technologies allowing transmission of voice across IP, Frame Relay, and ATM. G.711 is standard 64 kbps PCM modulation using either u-law or A-law. For a complete list of codecs supported, see Table 5 below.
Silence Suppression/Voice Activity Detection
Bandwidth is used only when someone is speaking. During silent periods of a phone call (approximately 50 percent of the time), bandwidth is available for data traffic.
Comfort Noise Generation
To better simulate phone calls over voice networks, this feature reassures the phone user that the connection is being maintained, even when no voice packets are being transmitted.
Dial Plan Mapping
Automatic mapping of dialed voice over IP phone numbers to IP addresses simplifies configuration and management.
Dual Tone Multifrequency (DTMF) Tone Processing
This feature enables access to voice mail and Interactive Voice Response (IVR) systems.
Fax and Modem Passthrough
Allows fax and modem traffic to pass through a voice port.
Fax Relay
Provides a more robust protocol for fax transmission over packet networks. Also supports the T.37 and T.38 fax protocols.
Country-Specific Signaling
This feature transparently delivers customary phone signals to users, facilitating acceptance of new technology.
Autocalling/PLAR
With this feature, a destination phone can be configured to automatically ring when the caller lifts the handset (also known as Private Line Automatic Ring-down-PLAR).
Hunt Groups
Calls can be forwarded automatically to the first available line.
Battery Polarity Reversal Detection and Initiation
Detection of disconnect supervision and far-end answer supervision via battery polarity reversal provides a robust method of providing supervisory disconnect especially for loop-start signaling on FXS and FXO interfaces.
Supervisory Disconnect
Signaling protocols such as loop-start do not provide means for quickly detecting when the call initiation is terminated prior to call connection. Supervisory disconnect quickly makes this determination and frees valuable resources for other calls.
FXO Power Failover
During power failure to the router, this feature enables a direct metallic path between an FXO port and a special "red" telephone to provide a direct line to the PSTN.
Table 5. Call Complexity and Codecs Supported
Call Complexity
List of Standard Codecs Supported
High Complexity
G.711 a-law and u-law; G.726 @ 32k, 24k, and 16k; G.729, A, B and AB; G.723.1 @ 5.3k and 6.3k; clear channel codec, and fax relay
Medium Complexity
G.711 a-law and u-law; G.726 @ 32k, 24k, and 16k; G.729A and AB; clear channel codec, and fax relay
SOFTWARE AND MEMORY REQUIREMENTS
Table 6. Cisco IOS Software Version Requirements
Product
Cisco 2600/3600
Cisco 2691/2600XM/3700
Cisco 2800
Cisco 3800
NM-HDA-4FXS
12.2(2)XT or 12.2(8)T
12.2(8)T
12.3(8)T4
12.3(11)T
EM-HDA-8FXS
12.2(2)XT or 12.2(8)T
12.2(8)T
12.3(8)T4
12.3(11)T
EM-HDA-4FXO
12.2(2)XT or 12.2(8)T
12.2(8)T
12.3(8)T4
12.3(11)T
EM2-HDA-4FXO
Not supported
12.3(14)T
12.3(14)T
12.3(14)T
DSP-HDA-16
12.2(2)XT or 12.2(8)T
12.2(8)T
12.3(8)T4
12.3(11)T
Please refer to the Cisco IOS® release notes for determining the minimum flash and DRAM memory requirements.
SPECIFICATIONS
Table 7. NM-HDA-4FXS Specifications
NM-HDA-4FXS
High-Density Analog Voice/Fax Network Module with Four FXS Ports
Cisco IOS Software Requirement
12.2(2)XT/12.2.(8)T or later
Cisco Part Number
800-07867-02
FCC Specifications
FCC Class B device
Safety Conformance
UL1950
Physical Connector(s)
One RJ-21
Spare
NM-HDA-4FXS=
DSP Type
TI 5421
Number of DSPs
2
Number of High Complexity Calls
8
Number of Medium Complexity Calls
16
Support for Expansion Modules
• Supports two EM slots
• One each of EM-HDA-8FXS
• One or two each of EM2-HDA-4FXO
• One or two each of EM-HDA-4FXO
Support for DSP Module
One each of DSP-HDA-16
FXS Port Specifications
See under EM-HDA-8FXS below
Mean Time Between Failures (MTBF)
789,000 hours (using Bellcore model)
Table 8. EM-HDA-8FXS Specifications
EM-HDA-8FXS
Eight-Port FXS Voice/Fax Expansion Module
Interface Type
Foreign exchange station
Cisco IOS Software Requirement
12.2(2)XT/12.2(8)T or later
Cisco Part Number
800-07868-02
Compliance
FCC Class B device, CE
Safety Conformance
UL1950
Spare
EM-HDA-8FXS=
Address Signaling Formats
• In-band DTMF
• Out-of-band pulse (10/20 pps)
Signaling Formats
Loop-start, ground-start
Ringing Tone
Configurable for different country requirements
Ringing Voltage
<45 Vrms at 3 REN at 25 Hz (configurable frequency)
Ringing Frequencies
20 Hz, 50 Hz
Physical Connector
None. Ports accessed through the RJ-21 connector on the NM-HDA-4FXS
MTBF
1,730,000 hours
Table 9. EM2-HDA-4FXO Specifications
EM2-HDA-4FXO
Four-Port FXO Voice/Fax Expansion Module
Interface Type
Foreign exchange office (supports loop .)
Cisco IOS Software Requirement
12.3(14)T
Cisco Part Number
800-25720-01
Compliance
FCC Class B device, CE
Safety Conformance
UL1950
Spare
EM2-HDA-4FXO=
Signaling Formats
Loop-start, ground-start
Address Signaling Formats
• In-band DTMF
• Out-of-band pulse (10/20 pps)
Tone Disconnect Supervision
Call disconnect on progress tone of less than 600 Hz
Battery Polarity Reversal Detection
Detection of disconnect supervision and far-end answer supervision via battery polarity reversal
Power Interrupt Disconnect
Call disconnect on power interrupt of more than 600 msec
Physical Connector
None. Ports accessed through the RJ-21 connector on the NM-HDA-4FXS
Power Failover Port
During power failure, one FXO port "fails over" (gets connected) to a standby port with an analog phone
MTBF
995,424 hours
Table 10. EM-HDA-4FXO Specifications
EM-HDA-4FXO
Four-Port FXO Voice/Fax Expansion Module
Interface Type
Foreign exchange office (for loop length up to 8,000 ft.)
Cisco IOS Software Requirement
12.2(2)XT/12.2.(8)T or later
Cisco Part Number
800-17607-01
Compliance
FCC Class B device, CE
Safety Conformance
UL1950
Spare
EM-HDA-4FXO=
Signaling Formats
Loop-start, ground-start
Address Signaling Formats
• In-band DTMF
• Out-of-band pulse (10/20 pps)
Tone Disconnect Supervision
Call disconnect on progress tone of less than 600 Hz
Battery Polarity Reversal Detection
Detection of disconnect supervision and far-end answer supervision via battery polarity reversal
Power Interrupt Disconnect
Call disconnect on power interrupt of more than 600 msec
Physical Connector
None. Ports accessed through the RJ-21 connector on the NM-HDA-4FXS
Power Failover Port
During power failure, one FXO port "fails over" (gets connected) to a standby port with an analog phone
MTBF
1,150,000 hours
Table 11. DSP-HDA-16 Specifications
DSP-HDA-16
16-Channel DSP Module for NM-HDA
Interface Type
No external interface
Cisco IOS Software Requirement
12.2(2)XT/12.2.(8)T or later
Cisco Part Number
800-07870-02
Compliance
FCC Class B device, CE
Safety Conformance
N/A
Spare
DSP-HDA-16=
DSP type
TI 5421
Number of DSPs
2
Number of High Complexity Calls
8
Number of Medium Complexity Calls
16
Physical Connector
No external connection
MTBF
5,007,000 hours
HOMOLOGATION
The following modules are approved for the countries listed below for off-premise and on-premise connections (approval for other countries in progress).
