ZyXEL Communications Multi-service Access Platform MSAP2000 - Manual (Page 103)

6. System Design
MSAP2000 Technical Manual V3.0 6-6
6.4. Reliability
MTBF
The devices and quality testing procedures applied towards
MSAP2000 Modules are guaranteed to provide over five years of
MTBF (Mean Time Between Failure), under full loading.
The following chart shows the reliability rate of each Module, as well as
each Module’s FIT (Failure Interval Time) calculated according to
MIL-HDBK-217F. Besides routine testing procedures, the Modules
are also subjected to testing at high temperatures and high humidity, to
double-confirm the results of FIT testing.
NOTE: FITS= Long Term Failure Rates in units per billion device hours
FITS of Each
Module Module FITS
Shelf 310
COT Power Supply Module (CoPSM)
977
RT Power Supply Module (RtPSM) 1018
Main Processing Module (MPM) 922
V5 Processing Module (V5P) 633
Packet Voice Module (PVM) 626
Expansion Processing Module (EPM) 621
STM-1 Optic Trunk/Interface Module (OIM) 674
STM-1 Module (SM1) 685
STM-4 Module (SM4) 690
Expansion Link Module (ELM) 623
Quad E1 Module (QE1M) 679
Ethernet Module (ETH) 645
G.SHDSL Module (GSH) 693
Foreign Exchange Office Module (FXO) 777
Foreign Exchange Office Payphone Module (FXO-P) 677
Foreign Exchange Station Module (FXS) 792
Foreign Exchange Station Payphone Module (FXS-P) 633
2W/4W Ear & Mouth Module (2W/4W E&M) 742
Metallic Line Testing Module (MLTM) 867
ISDN U Interface Network Terminal Module (LUNT) 653
ISDN U Interface Line Terminal Module (LULT) 687
COT Ethernet over SDH Module (CEoSM) 616
RT Ethernet over SDH Module (REoSM) 644
Giga-Bit Ethernet Module (GbE) 855
Ethernet Switching Module (ESM) 622
ADSL2/2+ Access Module (AAM) 788
According to the FIT numbers in the above chart, it can be seen based
on OIM that the MTBF of a fully loaded MSAP2000 COT is 5.7 years,
while that of a fully loaded RT is 5.5 years.