ZXMSG 5200 (V2.0) Technical Manual 
28  Confidential and Proprietary Information of ZTE CORPORATION 
IP Telephone Voice Performance 
IP Codes 
The ZXMSG 5200 service processing unit supports the following codes:  
  G.711 (5ms/10ms/20ms Ethernet packets) 
  G.729a (10ms/20ms Ethernet packets) 
  G.723.1 (30ms Ethernet packets) 
Coding Rate 
Different coding algorithms need gateways to have different coding rates: 
  For G.729a, the coding rate is required to be less than 18 kbps. 
  For G.723.1 (5.3), the coding rate is required to be less than 12 kbps; 
for G.723.1 (6.3) less than 15 kbps. 
Objective Evaluation on Voice 
  In a good network condition: PSQM mean value is less than 1.5. 
  Poor  network  condition  (packet  loss  ratio  =  1%,  network  jitter  =  20 
ms, delay = 100 ms): PSQM mean value is less than 1.8. 
  Worst  network condition (packet  loss  ratio  =  5%,  network  jitter = 60 
ms, delay = 400 ms): PSQM mean value is less than 2.0. 
Subjective Evaluation on Voice 
  In a good network condition: MOS > 4.0 
  Poor  network  condition  (packet  loss  ratio  =  1%,  network  jitter  =  20 
ms, delay = 100 ms): MOS > 3.5 
  Worst  network condition (packet  loss  ratio  =  5%,  network  jitter = 60 
ms, delay = 400 ms): MOS > 3.0 
Delay Indices 
The  delay  of  IP  telephone  can  mean  coding/decoding  delay,  input  buffer 
delay at the receiving end and internal queue delay. 
  G.729 delay is less than 150 ms. 
  G.723.1 delay is less than 200 ms.