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TR-41 VoIP Standards


Go there to download:

TIA-810-BTransmission Requirements for Narrowband Digital Telephones


TIA-811-A Performance and Interoperability Requirements for Voice-over-IP (VoIP) Feature Telephones


TIA-912-AVoice Gateway Transmission Requirements


TIA-920Transmission Requirements for Wideband Digital Wireline Telephones


TIA-1057 IP Telephony - Link Layer discovery Protocol For Media Endpoint Devices


TSB116-A Voice Quality Recommendations for IP Telephony


TSB146 IPTelephony Support for Emergency Calling Service


TSB32-A Overall Transmission Plan Aspects for Telephony in a Private Network

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Information You Can Use

Please check back for additions to this list.

Sound Power Measurement – A Quick Reference (1.3M pdf)


Download Information on sound power, sound intensity.


How to measure the sound power of a desktop device using an array of microphones to determine the average SPL and Sound Intensity and then calculate the Sound Power using data from these measurements.   The sound power is measured in a free field over a reflecting plane (table or floor).  In telephony this method has been used to measure the sound power of ringers (alerters).  Some recent telecom recommendations simplify the method to measuring the average SPL level at ½ meter using fewer microphone positions.


Siemens 8800 Handset Beeping Problem / Bad Charger Contacts

If your Siemens 8800 handset, for the Siemens 8825 telephone base, is beeping while in the charge stand you may have a problem with the charge-stand electrical contacts.  This can be remedied by cleaning the contacts in the charge stand with a light abrasive.  A Dermal tool with a wire brush tip works best but very fine sandpaper will also work.  Cleaning with a cotton swab, etc., is not sufficient.  You normally don’t have to clean the contacts on the handset itself.  Low batteries are another cause for beeping handsets.

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© Ron Magnuson,
Acoustics for Communications

Austin, Texas