---------- Original message from Duane J. Marcroft ---------- > Ben, > > I have a question: > > Where in the scenario you describe below does a modem fit that has: > > 1. A microphone and head-set. > 2. Digitatizes the voice. > 3. Voice transmission is passed through the modem as data? > > In essence voice transmission is not analogue. > > Duane
Duane This equipment is non-voice since it employs a microphone and head-set (points 2 and 3 don't really enter into this). CTR38 refers to HANDSET telephony terminal equipment capable of supporting the voice telephony justified case service. (i.e. must have a corded handset.) Generally in Europe approval requirements are only concerned that your network interface is compliant (i.e. you terminate the network correctly). There is no concern over end to end interworking (i.e. what you squirt down a PSTN / ISDN / leased line etc is not important). The exceptions to this are referred to as justified cases. As far as I know only three exist. Voice telephony justified case (CTR8 and CTR38). DECT telephony justified case (CTR10) and GSM telephony justified case (CTR20). They are designed to ensure end to end interworking with a minimum level of quality. If you were purchasing an item of terminal equipment principally for voice communication over the PSTN with quality in mind, you wouldn't buy a modem with microphone and headset, you'd go for a telephone with handset. This is why handsfree/loudspeaking functions, cordless telephones etc. are excluded from the voice justified case. Added to the above, it would be very difficult to approve a modem with microphone and headset as you describe since such a modem could theoretically be used with any standard microphone and headset. How do you test acoustic requirements in such a scenario? The microphone and headset are indirectly connected and so are not subject to approval requirements (although it would be necessary to apply an acoustic stimulus the microphone port during PSTN access testing in the same way as you would apply a stimulus to any data port). The same is true for POTS ports on ISDN routers. The POTS port would have to be stimulated during ISDN access testing but equipment connected to the POTS port would not be subject to testing or approval since it's indirectly connected. (A lot of POTS equipment can of course be directly connected to the PSTN as well and so is tested and approved anyway.) I hope this helps. Regards ------------------------------ Ben Wrigley Senior Approvals Specialist KTL Saxon Way Priory Park West Hull HU13 9PB UK Phone: +44 (0)1482 801801 Fax: +44 (0)1482 801806 Mobile: +44 (0)802 280914 Web: http://www.ktl.com Email: mailto:[email protected]
