- Reset gateway to factory default and ensure you are running the latest firmware.
- Review vendor documentation and assign a IP / Subnet mask / default router or gateway / DNS entries to the device. Ensure you are documenting all this with notes and screenshots for eventual publication as an FAQ.
- Disable any automatic firmware upgrades to ensure the device remains on the tested firmware.
- After having created the gateway (and its ports within 3CX using the Generic Gateway template) you will need to add the ports to the gateway.
- Follow vendor documentation to find out where the port entries must be made.
- Typically the port settings will require Channel number / Authentication ID / Authentication Password. The Authentication ID and Authentication Password can be left to the defaults suggested by 3CX.
- Ask the Telecoms company for their expected DTMF signaling lengths and volume
- Ask the Telecoms company for the mechanism they use to send the Caller ID. There are various standards and can vary.
- Set PSTN fax to T38 settings to allow a maximum speed of 9600bps if testing FAX capabilities for the gateway.
- Check Polarity reversal requirements with your Telecoms company.
- Recommended Codec priority should be set to G711U / G711A / G729 / GSM for Voice calls.
- Recommended codec for fax is T38 as primary codec and maximum allowed speed should be 9600. Other codecs are NOT supported for FAX interaction.
- Set RTP Packet time to 20ms.
- Set DTMF options to RFC2833 as this is the most reliable for PSTN gateways.
Testing of gateway once configured
- Check registration settings and ensure device registers for each configured port.
- Ensure default registration time is set to 900 (or the closest value to this as possible).
- Make an inbound call to the phone – ensure 2-way audio.
- Make an inbound call to the phone and place caller on hold – ensure Music On Hold (MOH) is heard
- Resume call – ensure 2-way audio
- Make an attended transfer of an inbound call – ensure caller hears MOH, and caller is successfully transferred including 2-way audio.
- Make a blind transfer of an inbound call – ensure caller hears MOH, and caller is successfully transferred including 2-way audio.
- Ensure outbound Caller ID appears as expected.
- Ensure inbound Caller ID appears as expected.
- Make inbound call to a DR and ensure all MOH, audio are heard as expected.
- Making an inbound call to a DR, test all DTMF tones from 0-9 and ensure they are accepted correctly, predictably.
- Making an outbound call to some Auto Attendant/DR service, test all DTMF tones from 0-9 and ensure they are accepted correctly, predictably.
- Receive an inbound call through the gateway and divert this through the PBX to an outside number, exiting via the same entry device. NOTE: This is not a valid/necessary test in the case of a single-FXO gateway device.