AudioCodes Mediant 3000 User Manual page 248

When the device has BITS capability, configure the following parameter in addition to the
above parameters:

TMMode =2 - defines the BITS mode (set this to 2 for line interface clock)
Notes:
18.1.1.3.1.2 Configuring BITS Synchronization Mode
This section describes how to configure the device to use Building Integrated Timing
Source (BITS) clock inputs to synchronize the system to an external BITS source.
In BITS synchronization mode, the clock flows from the BITS to the line interfaces. In this
mode, both active and redundant blades are synchronized by two BITS input trunks. The
BITS trunks flow through two SAT blades (housed in the chassis), each with a designated
timing module. Two SAT blades are required to ensure seamless clock operation in case of
failure of one of the SATs timing modules (i.e., clock redundancy).
You first need to define the external BITS reference transmission type for both primary and
secondary interfaces connected to the device, using the TMExternalIFType parameter:

[0] E1 CRC4 (default)

[1] E1 CAS

[2] E1 FAS

[3] T1 D4

[4] T1 ESF

[5] T12
Other physical characteristics of the BITS interface can be set with the following
parameters:

TMT1LineBuildOut: defines the transmission power between the timing module on the
SAT blade and the T1 external reference clock (External Reference Transmit Line
Build Out):
•
[0] = DSX 1.0 to 133 feet 0 dB CSU
•
[1] = DSX 1.133 to 266 feet (default)
•
[2] = DSX 1.266 to 399_feet
•
[3] = DSX 1.399 to 533 feet
•
[4] = DSX 1.533 to 655 feet
•
[7] = DSX 1.0 to 133 feet 0 dB CSU pulse enable transmit and receive gapped
clock

TME1LineBuildOut: defines the transmission power (in Ohm) between the timing
module on the SAT blade and the E1 external reference clock:
•
[0] E 75 ohms normal
•
[1] E 120 ohms normal (default)
•
[4] E 75 ohms with high return loss
•
[5] E 120 ohms with high return loss
•
[6] E 75 ohms normal plus enable transmit and receive gapped clock
•
[7] E 120 ohms normal plus enable transmit and receive gapped clock
SIP User's Manual
•
When operating in line recovery mode and the device is installed with the
BITS timing hardware, when the source link/trunk clock reference fails,
both active and redundant blades change to hold-over mode.
•
When the device does not have the BITS timing hardware installed, set
TMMode to 0 (default).
248
Mediant 3000
Document #: LTRT-89712