Specifications

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Linksys ATA Administrator Guide
Document Version 3.1
Chapter 3 Configuring Linksys ATAs
Using a FAX Machine with the SPA2102 or SPA8000
Step 1 Upgrade the ATA firmware to the latest version
Step 2 Ensure that you have enough bandwidth for uplink and downlink.
• For G.711 fallback, it is recommend to have ~100Kbps.
• For T.38, allocate at least 50 kbps.
Step 3 To optimize G.711 fallback fax completion rates, use the following settings on the Line tab of the
Linksys ATA:
• Network Jitter Buffer: very high
• Jitter buffer adjustment: disable
• Call Waiting: no
• 3 Way Calling: no
• Echo Canceller: no
• Silence suppression: no
• Preferred Codec: G.711
• Use pref. codec only: yes
Step 4 If you are using a Cisco media gateway for PSTN termination, disable T.38 (fax relay) and enable fax
using modem passthrough.
For example:
modem passthrough nse payload-type 110 codec g711ulaw
fax rate disable
fax protocol pass-through g711ulaw
Step 5 Enable T.38 fax on the SPA 2102 by configuring the following parameter on the Line tab for the FXS
port to which the FAX machine is connected:
FAX_Passthru_Method: ReINVITE
Note If a T.38 call cannot be set-up, then the call should automatically revert to G.711 fallback.
Step 6 If you are using a Cisco media gateway use the following settings:
Make sure the Cisco gateway is correctly configured for T.38 with the SPA dial peer. For example:
fax protocol T38
fax rate voice
fax-relay ecm disable
fax nsf 000000
no vad
Troubleshooting
If have problems sending or receiving faxes, complete the following steps:
Step 1 Send a test Fax in a controlled environment between two Linksys ATAs.
Step 2 Determine the success rate.
Step 3 Monitor the network and record the following statistics:
• Jitter