Each T1/E1 port can be independently configured for loop-timing (recovered from an Rx line) or node-timing (recovered from the SSU in the active CSM).
In addition, T1/E1 CES circuits on the following can be independently configured for adaptive timing (clocking is derived from incoming TDM pseudowire packets):
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
7705 SAR-M (variants with T1/E1 ports)
7705 SAR-X
7705 SAR-A (variant with T1/E1 ports)
T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module
T1/E1 CES circuits on the following can be independently configured for differential timing (recovered from RTP in TDM pseudowire packets):
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
4-port OC3/STM1 / 1-port OC12/STM4 Adapter card (DS1/E1 channels)
4-port DS3/E3 Adapter card (DS1/E1 channels on DS3 ports; E3 ports cannot be channelized); differential timing on DS1/E1 channels is supported only on the first three ports of the card
7705 SAR-M (variants with T1/E1 ports)
7705 SAR-X
7705 SAR-A (variant with T1/E1 ports)
T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module
A T1/E1 port can be configured to be a timing source for the node.
Adaptive timing and differential timing are not supported on DS1 or E1 channels that have CAS signaling enabled.