Cisco Cisco NM-2V Two Voice Fax Interface Card Slot Network Module Manual Técnica
Conventions
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Background Information
This section provides background information About High−Density Analog and Digital Extension Module for
Voice/Fax.
Voice/Fax.
Key Features
The High−Density Analog and Digital Extension Module for Voice/Fax supports the following:
Analog FXS, analog Foreign Exchange Office (FXO), DID, and digital BRI S/T NT/TE
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Generic DSPware feature support: silent suppression, tone detection, voice codec
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The following new expansion modules:
EM−HDA−3FXS/4FXO−−3−port FXS and 4−port FXO voice/fax expansion module
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EM−HDA−6FXO−−6−port FXO voice/fax expansion module
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EM−4BRI−NT/TE−−4−port ISDN BRI expansion module
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The existing EM−HDA−8FXS expansion module
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G.168 ECAN echo−cancellation support
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Signaling types:
FXO and FXS: Ground−start and loop−start
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DID: Wink−start, immediate−start, and delay−start
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VoX (Voice over Packet) protocol support:
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VoIP for H.323, Media Gateway Control Protocol (MGCP), Session Initiation Protocol (SIP) as
supported by Cisco IOS software
supported by Cisco IOS software
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VoFR or VoATM as supported by Cisco IOS software
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Channel−bank emulation and cross connect
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Hairpinning:
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Digital to digital (same card)
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Analog to digital (same card)
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BRI ports with inline power support
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BRI S/T NT/TE support, clock distribution, synchronization
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REN support: five RENs per port
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FXS and FXO Interfaces
An FXS interface connects the router or access server to end−user equipment such as telephones, fax
machines, or modems. The FXS interface supplies ring, voltage, and dial tone to the station. An FXO interface
is used for trunk, or tie line, connections to a PSTN CO or to a PBX. This interface is of value for
off−premises station applications.
machines, or modems. The FXS interface supplies ring, voltage, and dial tone to the station. An FXO interface
is used for trunk, or tie line, connections to a PSTN CO or to a PBX. This interface is of value for
off−premises station applications.
FXO and FXS interfaces indicate on−hook or off−hook status and the seizure of telephone lines by one of two
access signaling methods: loop−start or ground−start. The type of access signaling is determined by the type
of service from the CO; standard home telephone lines use loop−start, but business telephones can use
ground−start lines instead.
access signaling methods: loop−start or ground−start. The type of access signaling is determined by the type
of service from the CO; standard home telephone lines use loop−start, but business telephones can use
ground−start lines instead.
Loop−start is the more common of the access signaling techniques. When a handset is picked up (the
telephone goes off−hook), this action closes the circuit that draws current from the telephone company CO
and indicates a change in status, which signals the CO to provide dial tone. An incoming call is signaled from
the CO to the handset by a standard on/off pattern signal, which causes the telephone to ring.
telephone goes off−hook), this action closes the circuit that draws current from the telephone company CO
and indicates a change in status, which signals the CO to provide dial tone. An incoming call is signaled from
the CO to the handset by a standard on/off pattern signal, which causes the telephone to ring.