The PA-VXA/VXB/VXC voice port adaptors for the Cisco
7200/7300/7400/7500 router platforms combine T1/E1 connectivity and onboard
digital signal processor (DSP) resources. This provides flexibility and power
to directly support voice services on these gateways. These port adaptors can
support either T1 or E1 interfaces. Based on the selected model, the port
adaptors can support up to 60 simultaneous High Complexity (HC) or 120
simultaneous Medium Complexity (MC) codec algorithm voice calls. Additionally
(based on the selected model), it is possible to use the onboard DSPs as a DSP
farm to provide voice services to port adaptors such as the PA-MCX-nTE1 series
of products. These can support voice Telephony interfaces but have no direct
DSP resources of their own.
This document is primarily targeted towards voice port adaptors
supported on the Cisco 7200/7300/7400/7500 platforms since Cisco IOS® Software
Release 12.1(3)T or later. The older PA-VXB-2TE1 and PA-VXC-2TE1 port adaptors
are no longer supported in Cisco IOS Software releases later than 12.1(3)T and
are not recognized at router boot-time. Refer to
Gateway Hardware Compatibility Matrix (Cisco 7200, 7300, 7400, 7500) for
information on these legacy voice port adaptors as well as the current line of
voice port adaptors.
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
3 The PA-VXA-1TE1-24+ is intended for T1
connectivity with MC codecs while the PA-VXA-1TE1-30+ is intended for E1
connectivity with MC codecs. You need to consider the PA-VXC-2TE1+ product for
T1 or E1 support with HC codecs.
Note: The Cisco IOS Software releases provided are typically the minimum
release required to support the platform, module, or feature in question. To
find out a complete list of Cisco IOS Software releases a feature, module,
interface card, or chassis is supported in, use the
(registered customers only)
The PA-VXA supports one software-selectable T1 or E1 interface. The
PA-VXB and PA-VXC support two software-selectable T1 or E1 interfaces; both
interfaces must be the same.
T1 interface features include:
DS1 100-ohm interface with RJ-48C connectors
D4 superframe (SF) or extended superframe (ESF)
Alternate Mark Inversion (AMI) or Binary 8-Zero Substitution (B8ZS)
Full Facilities Data Link (FDL) support and FDL performance
monitoring compliant with ANSI T1.403 or AT&T TR 54016
Software-selectable DSX-1 cable length in increments from 0 to 655
Software-selectable DS1 CSU line build-out settings for 0 dB, -7.5
dB, -15 dB, and –22.5 dB
Software-selectable DS1 CSU receiver gain settings for 26 dB or 36
DS1 line protection per UL1459/1950, FCC part 68
Full support for DSX-1 MIB RFC 1406, including alarm detection and
DSX-1 MIB remote access is supported
E1 interface features include:
E1 120-ohm (G.703) with RJ-48C connectors
Software-configurable E1 national bits
CRC4 or non-CRC4 framing
HDB3 or AMI line encoding
Full support for E1 MIB, RFC 1406, including alarm detection and
DS0 Drop-and-Insert (D&I)
The PA-VXA/VXB/VXC Voice Port Adaptors use Texas Instruments C549
DSPs. Each DSP:
Runs up to four voice calls in MC codec mode (G.711, G.729a,
G.729ab, G.726, and FAX relay).
Runs up to two voice calls in HC codec mode (G.729, G.729b, G.728,
G.723.1, GSM/EFR, + all MC codecs).
FAX support includes T.30 FAX protocol with relay, V.17, V.29,
V.27, T.38 FAX protocol with relay.
Software Echo Cancellation up to 32 ms coverage compliant with
ITU-T G.165, until Cisco IOS Software Release 12.2(13)T when 64 ms coverage
becomes available with the
ITU-T G.168 Echo Cancellation feature.
DTMF/R2/MF/SF/CP tone detection and generation
Dial-pulse detection and generation
Energy-based Voice Activity Detection (VAD) and codec-specific VAD