Specifications

Chapter 5 12-Channel FXO & Dial Pulse Termination
5-3
DIAL PULSE TERMINATION (DPT) TERMINATION
CO
DPO* DPT
PBX
Direct Inward Dial (DID)
T1
Calling
Party
Called
Party’s
Direct
Extension
* Use CAC’s Battery Reversal
FXS/DPO 12 Channel Analog Card
Figure 6-4: DPT Operation
In DPT mode, the FXO/DPT offers near end termination for one-way Direct Inward Dial (DID). Two-way DID
is provided by CAC’s 4 wire E&M interface. Functionally, the DPT card interprets T1 signaling bits to: 1)
provide incoming seizure, 2) act as a current “sink” for a PBX -48V battery source, 3) establish an audio path,
and 4) detect battery reversal from the PBX for call progress and confirmation of call completion.
4-Position DIP Switch
per Card
Slide Switch
per Channel
1
LS
ON
GS
0
Figure 6-5: DPT Loop Start Switch Settings
CHANNEL ATTENUATION OPTIONS
Each channel on the FXO/DPT can be individually configured to separately attenuate the audio frequency signal
in the transmit and receive directions. The level of loss is selected via a 6-position DIP switch for each channel
(12 per card), and is measured in decibels (dB). Note that a 3dB loss implies the average power is reduced by
50%.
RECEIVE LOSS IN DB
Table 6-2: Transmission Gain Options and Switch Settings for the FXO/DPT
Switch Position
1 2 3
Switch Setting
ON
0 0 0
OFF
-2 -3 -4
Transmit loss in dB