Lucent Technologies PacketStar PSAX, User Manual, Page: 338 / 405

255-700-243 B-29
PacketStar
®
PSAX 12-Port Medium-Density DS1 Multiservice Module User Guide , Issue 1 Release 8.0
Appendix B Reference Information
Module Alarm Status Table
Fax Relay Using AAL2 Requirements
Table B-2 shows the cell rate for fax relay modulation/demodulation using
Algosets 4 or 6 on the DSP2C or DSP2D Voice Server modules.
•
Changing rates of 8 Kbps to 14.4 Kbps fax requires an additional 14
cells/sec.
• Changing rates of 8 Kbps to 12.0 Kbps fax requires an additional 8
cells/sec.
•
Changing rates of 8 Kbps to 9.6 Kbps fax requires an additional 1 cell/sec.
Fax relay mode contains 20 msec of data for every cps packet, so the cell rate
is more efficient than for voice codec.
The change in bandwidth is controlled by the DSP host code. If insufficient
bandwidth is available on the AAL2 trunk, the fax will be forced to a lower
rate. DSP resources must be available or the fax will fail. In addition, fax
modem bypass or fax relay/modem bypass is supported if enough bandwidth
is available on the AAL2 trunk.
Module Alarm Status Table
The alarm status descriptions for the Alarm Status field on the Equipment
Configuration window are provided in Table B-8. When underscored num-
bers are displayed in this field, they represent one or more ports on the mod-
ule that currently have a loss of signal.
Table B-7. Non-Multiplexed AAL2 Transmission Rates
Compression Rate (in Kbps) Cell/sec
64 200
40 200
32 100
24 100
16 50
8 25
Table B-2. Standard AAL2 Bandwidth Calculation for Fax Relay Mode Using DSP AlgoSets 4 or 6
Compression
Rate (in Kbps)
Data
Bytes
/sec
Data + Overhead
Calculation
Data +
Overhead
/sec
Cells/sec
calculation
Cells
/sec
Average
Expected
cells/sec with
silence enabled
14.4 1800 1800/(36*39) 1950 1950/47 42 N/A
12.0 1500 1500/(30*33) 1650 1850/47 36 N/A
9.6 1200 1200/(24*27) 1350 1350 29 N/A