The maximum length of the TDM is dependent upon 3 factors:

1. the type of TDM card in the DACS
2. the type of TDM cable used to create the ring
3. the sample rate of the model

This assumes that the RIUs used to create the TDM ring are version 4.1 with RIU firmware 2.3.1 or higher. This equates to ASTi part number RIU-V41-AA.

Surface-Mount TDM, PC-104 TDM and Cat-5 cables**
Using 8 kHz sample rate: 700 feet
Using 16 kHz sample rate: 350 feet
Using 24 kHz sample rate: 140 feet

** Due to the long ring lengths achieved with Cat-5 cables, Cat-6 cables were not tested with the surface mount TDM.

Through Hole TDM and Cat-5 cables
Using 8 kHz sample rate: 490 feet
Using 16 kHz sample rate: 210 feet

Through Hole TDM and Cat-6 cables
Using 8 kHz sample rate: 490 feet
Using 16 kHz sample rate: 280 feet

The ring lengths listed above were obtained under lab conditions using manufactured cables. Ambient electrical noise conditions, cable/connector quality, and other installation anomalies could reduce these lengths.