ProGrid: When would I need to use / quote a ProGrid product with SRC (sample rate conversion)?

The Clear-Com 2014 price list shows the following parts
ProGrid 8 AES3 SRC If MM:  1RU, 1 x 8 channel AES3 I-O withinternal sample rate convertor, Dual PSU, Multi Mode fiber & SANE TwistedPair CAT5.  ProGrid 8 AES3 If MM:  1RU, 1 x 8 channel AES3 I-O, Dual PSU, Multi Mode fiber & SANETwisted Pair CAT5.
Answer: The standard version is without SRC and this is recommendedone, because SRC degrades audio quality.
When you use the product without SRC the 3rd party AES device needs to belocked - either to the AES signal that we provide or via BNC Word Clock cable.
SRC device should be used when the external device cannot be locked to AES orWordClock - quite common in AES CD players.