PVDM 支持数字语音连接、会议、通用转码和媒体优化服务:
● T1/E1 语音: PVDM 的主要用途之一是将数字语音打包成 IP 数据包,以启用时分复用 (TDM) 数字语音应用。
● 会议: PVDM 模块支持与 Cisco Unified Communications Manager 和 Cisco Unified Communications Manager Express 结合使用的各种编解码器的临时会议和即时会议。
● 通用转码:与 Cisco IOS ®软件结合使用时,PVDM 支持通用转码,允许从任何支持的编解码器转换为任何其他支持的编解码器。
●速率转换 : PVDM 支持速率转换,将相同的编解码器重新打包,以连接具有不同编解码器打包周期的不同网络。
● 语音质量管理: PVDM 执行压缩、语音活动检测、抖动管理和回声消除。PVDM 中提供的回声消除具有 128 毫秒的尾部长度,并符合 ITU-T G.168。
● 节能:主板PVDM(PVDM4s)提供多种省电模式,包括不使用模块时的省电模式。在省电模式下,每个 PVDM4 最多可节省 5 瓦电力。
Catalyst 8000 和 4000 系列 ISR 的模拟语音模块(FXS、FXO 和 E/M)和基本速率接口 (BRI) 数字语音模块包含内置的、不可配置的数字信号处理器 (DSP),不需要任何用于语音分组的附加 PVDM。
有关常见问题,请参阅PVDM 问答。
Cisco PVDM 提供三种外形尺寸,每种外形尺寸支持四种密度:
● 主板 PVDM (PVDM4),密度高达 256 个通道(图 1)
● PVDM 增强型服务模块 (SM-X-PVDM),密度高达 3080 个通道(图 2)
● NIM PVDM,密度高达 256 个通道(图 3)
除 ISR 4461 外,所有 Cisco 4000 系列 ISR 都支持主板 PVDM。它们可以直接插入路由器主板上的单个插槽或插入支持 T1/E1 端口的网络接口模块 (NIM)。插入主板的 PVDM4 模块仅提供基于 IP 的语音服务,例如会议、媒体优化和转码。
插入 T1/E1 NIM 的 PVDM4 模块将用于语音 T1/E1 连接。任何多余的通道都可以重新用于主板插槽支持的其他基于 IP 的服务。增强型 DSP 架构可容纳针对富媒体语音应用优化的新数据包处理引擎,同时支持 TDM-IP 语音框架。
所有包含 SM-X 插槽的 Catalyst 8300 和 ISR(即 Cisco 4331、4351、4451 和 4461 ISR)都支持 PVDM 增强型服务模块。
Catalyst 8300s 和 ISR 4461 支持 PVDM 网络接口模块,它们都包含 NIM 插槽。
SM-X 模块和 NIM PVDM 模块仅支持基于 IP 的语音服务,不能用于 TDM 应用。
Table 1. Cisco PVDM Part Numbers and Slot Requirements
| Part Number | Slot | Description | 
| PVDM4-32(=) | On-board motherboard or T1/E1 module slot | 32-channel high-density voice DSP module, or spare | 
| PVDM4-64(=) | On-board motherboard or T1/E1 module slot | 64-channel high-density voice DSP module, or spare | 
| PVDM4-128(=) | On-board motherboard or T1/E1 module slot | 128-channel high-density voice DSP module, or spare | 
| PVDM4-256(=) | On-board motherboard or T1/E1 module slot | 256-channel high-density voice DSP module, or spare | 
| SM-X-PVDM-500(=) | Enhanced services module slot | 768-channel high-density voice DSP module, or spare | 
| SM-X-PVDM-1000(=) | Enhanced services module slot | 1024-channel high-density voice DSP module, or spare | 
| SM-X-PVDM-2000(=) | Enhanced services module slot | 2048-channel high-density voice DSP module, or spare | 
| SM-X-PVDM-3000(=) | Enhanced services module slot | 3080-channel high-density voice DSP module, or spare | 
| NIM-PVDM-32(=) | Network Interface module slot | NIM PVDM with 32-channel DSP | 
| NIM-PVDM-64(=) | Network Interface module slot | NIM PVDM with 64-channel DSP | 
| NIM-PVDM-128(=) | Network Interface module slot | NIM PVDM with 128-channel DSP | 
| NIM-PVDM-256(=) | Network Interface module slot | NIM PVDM with 256-channel DSP | 
Table 2. Voice, Fax, and Modem Codec Support on PVDMs
| Low-Complexity Codecs | Complexity | Motherboard PVDMs (PVDM4s) | PVDM Enhanced Services Modules (SM-X-PVDMs) | NIM PVDM Modules | 
| Clear channel | Low | Supported | Not applicable | Supported | 
| G.711 | Low | Supported | Supported | Supported | 
| Fax and modem pass-through | Low | Supported | Not supported | Supported | 
| G.722 | Medium | Supported | Supported | Supported | 
| G.726 | Medium | Supported | Not supported | Supported | 
| G.728 | High | Supported | Not supported | Supported | 
| G.729 | High | Supported | Supported (mapped to G.729a) | Supported | 
| G.729a | Medium | Supported | Supported | Supported | 
| G.729b | High | Supported | Supported (mapped to G.729ab) | Supported | 
| G.729ab | Medium | Supported | Supported | Supported | 
| Fax Relay | Medium | Supported | Not supported | Supported | 
| iLBC (Internet low bit rate codec) | High | Supported | Supported | Supported | 
| iSAC (Internet speech audio codec) | High | Transcoding only | Transcoding only | Transcoding only | 
| AMR-WB | High | Not supported | Not supported | Not supported | 
| Modem relay | High | Supported | Not supported | Supported | 
Table 3. Channel Densities of PVDM4, NIM-PVDM-X and SM-X-PVDM Modules
| Name | Number of Channels | ||
| Low Complexity | Medium Complexity | High Complexity | |
| PVDM4-32 | 32 | 24 | 16 | 
| PVDM4-64 | 64 | 48 | 32 | 
| PVDM4-128 | 128 | 96 | 64 | 
| PVDM4-256 | 256 | 192 | 128 | 
| SM-X-PVDM-500 | 768 | 384 | 192 | 
| SM-X-PVDM-1000 | 1024 | 512 | 256 | 
| SM-X-PVDM-2000 | 2048 | 1024 | 512 | 
| SM-X-PVDM-3000 | 3080 | 1400 | 770 | 
| NIM-PVDM-32 | 32 | 24 | 16 | 
| NIM-PVDM-64 | 64 | 48 | 32 | 
| NIM-PVDM-128 | 128 | 96 | 64 | 
| NIM-PVDM-256 | 256 | 192 | 128 | 
Table 4. Media-Enhancement Features
| Feature | Motherboard PVDMs (PVDM4s) | PVDM Enhanced Services Modules (SM-X-PVDMs) | NIM PVDM Modules | 
| Echo cancellation | Yes | No | Yes | 
| Tone detection | Yes | Yes | Yes | 
| Noise reduction | Yes | Yes | Yes | 
| Acoustic shock prevention | Yes | Yes | Yes | 
| Gain control | Yes | Yes | Yes | 
Table 5. Platform Availability for SM-X-PVDM Modules
| 4000 Series Platform | SM-X-PVDM-500 (maximum channels) | SM-X-PVDM-1000 (maximum channels) | SM-X-PVDM-2000 (maximum channels) | SM-X-PVDM-3000 (maximum channels) | 
| C8300-1N1S-6T | 1 (500) | 1 (1000) | 1 (2000) | 1 (3000) | 
| C8300-1N1S-4T2X | 1 (500) | 1 (1000) | 1 (2000) | 1 (3000) | 
| C8300-2N2S-6T | 2 (1000) | 2 (2000) | 1 (2000) | 1 (3000) | 
| C8300-2N2S-4T2X | 2 (1000) | 2 (2000) | 2 (4000) | 2 (6000) | 
| 4321 | Not supported | Not supported | Not supported | Not supported | 
| 4331 | 1 (500) | 1 (1000) | Not supported | Not supported | 
| 4351 | 2 (1000) | 1 (1000) | Not supported | Not supported | 
| 4431 | Not supported | Not supported | Not supported | Not supported | 
| 4451 | 2 (1000) | 2 (2000) | 1 (2000) | 1 (3000) | 
| 4461 | 3(1500) | 3 (3000) | 2 (4000) | 2 (4000) | 
All SM-X-PVDM modules require minimum of 8GB RAM
Table 6. Platform Performance for Transcoding
| Platform | Low Complexity to Low Complexity | 
| C8300-1N1S-6T | 3336 | 
| C8300-1N1S-4T2X | 3336 | 
| C8300-2N2S-6T | 3592 | 
| C8300-2N2S-4T2X | 6672 | 
| 4321 | 768 | 
| 4331 | 1024 | 
| 4351 | 1280 | 
| 4431 | 1024 | 
| 4451 | 3336 | 
| 4461 | 6160 | 
Table 7. Platform Performance for Conferencing
| Platform | Low Complexity (8-party) | 
| C8300-1N1S-6T | 498 | 
| C8300-1N1S-4T2X | 520 | 
| C8300-2N2S-6T | 591 | 
| C8300-2N2S-4T2X | 937 | 
| 4321 | 130 | 
| 4331 | 220 | 
| 4351 | 245 | 
| 4431 | 241 | 
| 4451 | 502 | 
| 4461 | 850 | 
Note that the 4000 Series ISRs do not support the PVDM3 modules, and the 2900 and 3900 Series ISRs do not support the PVDM4, SM-X-PVDM and NIM-PVDM-X modules.
Table 8 gives the specifications for the PVDM4 and SM-X-PVDM modules.
Table 8. Module Specifications
| Feature | Motherboard PVDMs (PVDM4s) | PVDM Enhanced Services Modules (SM-X-PVDMs) | PVDM Network Interface Modules (NIM-PVDM-X) | 
| Components | |||
| DSP | Multicore DSP technology | Multicore DSP technology | Multicore DSP technology | 
| Interface | Integrated Services Card (ISC) slot on motherboard or T1/E1 NIM | Enhanced services module (SM-X) | Network Interface module (NIM-PVDM-X) | 
| Features | |||
| Operating temperature | 32° to 122°F (0° to 50°C) | 32° to 104°F (0° to 40°C) | 32° to 122°F (0° to 50°C) | 
| Voltage | 3.3V | 12V | 12V | 
| Current | 1.47A | 4.17A | 1.25A | 
| Power | 4.85W | 50W | 15W | 
| Weight | 0.08 lb (36 g) | 1.78 Ib (808 g) | 0.45lb (204 g) | 
| Dimensions (H x W x D) | 0.67 x 2.50 x 2.62 in. (1.7 x 5.1 x 6.7 cm) | 1.58 x 8.55 x 8.10 in. (4.0 x 21.7 x 20.6 cm) | 1.25 x 3.50 x 7.24 in. (3.18 x 8.89 x 18.39 cm) | 
| Regulatory and Compliance | |||
| Safety | Complies with: ● IEC 60950 (worldwide) ● AS/NZS 60950-1 (Australia and New Zealand) ● CAN/CSA-C22.2 No. 60950-1, 1 st and 2 nd Ed. (Canada) ● GB4943-95 (People's Republic of China) ● EN60950-1, 1 st and 2 nd Ed. (CENELEC; includes EU and EFTA) ● NOM-019-SCFI-1998 (Mexico) ● UL 60950-1, 1 st and 2 nd Ed. (United States) | Complies with: ● IEC 60950 (worldwide) + A1 and A2 ● AS/NZS 60950-1 (Australia and New Zealand) ● CAN/CSA-C22.2 No. 60950-1, 2 nd Ed. (Canada) ● GB4943-95 (People's Republic of China) ● EN60950-1, 2 nd Ed. (CENELEC; includes EU and EFTA) plus Am1 and Am2 ● NOM-019-SCFI-1998 (Mexico) ● UL 60950-1, 2 nd Ed. (United States) | Complies with: IEC 60950-1, 2nd Ed with all group differences and national deviations (worldwide) ● CAN/CSA-C22.2 No. 60950-1-07. (Canada) ● EN 60950-1, 2 nd Ed. (CENELEC; includes EU and EFTA) ● UL 60950-1, 2 nd Ed. (United States) ● IEC 62368, 2 nd Ed with all group differences and national deviations (worldwide) ● CAN/CSA-C22.2 No. 62368-1-14. (Canada) ● EN 62368-1, 2 nd Ed. (CENELEC; includes EU and EFTA) ● UL 62368-1, 2 nd Ed. (United States) | 
| Homologation | Platform dependent | Platform dependent | Platform dependent | 
| Mean time between failures (MTBF) | System dependent | System dependent | System dependent | 
| EMC | |||
| Emissions | ● CISPR22, Class B ● EN55022, Class B, CFR47, Part 15, Subpart B, Class B | ● CISPR22, Class A ● EN55022, Class A, CFR47, Part 15, Subpart B, Class B | ● CISPR32, Class A ● EN55032, Class A, CFR47, Part 15, Subpart B, Class A | 
| Harmonics | EN61000-3-2 | EN61000-3-2 | EN61000-3-2 | 
| Flicker | EN61000-3-3 | EN61000-3-3 | EN61000-3-3 | 
| Immunity | ● CISPR24 ● EN 55024 ● EN50082-1 | ● CISPR24 ● EN 55024 ● EN50082-1 | ● CISPR24 ● EN 55024 ● EN61000-6-1 | 
| Electrostatic discharge (ESD) | EN 61000-4-2 | EN 61000-4-2 | EN 61000-4-2 | 
| RF fields | EN 61000-4-3 | EN 61000-4-3 | EN 61000-4-3 | 
| EFT | EN 61000-4-4 | EN 61000-4-4 | EN 61000-4-4 | 
| Surge | EN 61000-4-5 | EN 61000-4-5 | EN 61000-4-5 | 
| Conducted RF | EN 61000-4-6 | EN 61000-4-6 | EN 61000-4-6 | 
| Power-frequency magnetic fields | EN 6100-4-8 | EN 6100-4-8 | EN 6100-4-8 | 
| Voltage dips, sags, and interruptions | EN 61000-4-11 | EN 61000-4-11 | EN 61000-4-11 | 
 
     
     
     
     
     
  