In a message dated 96-06-20, Jeff Welsh writes: >I am invovled with basic (Plain Old Telephones) that are used mostly in the USA. >We have an inquiry to use them both in Italy and the Czech Repulblic. > >Aside from the agency approvals, does anyone know what typical issues must >be adressed? I'm having difficulty in getting the specs. Does it invoolve >total redesign or just the front end? > > Jeff:
To my knowledge, the current spec for POTS phones in Italy is CEI 103-5. The requirements are quite extensive. A translation of this spec can be obtained from BSI Language Services for about 620 pounds. Their fax number is 011-44-181-996-7047. I have the Czech spec for fax equipment, but not for POTS phones. The most notable aspect of the Czech requirement that I have is that the ringer capacitance must exceed 0.8 uF, and the total ringer impedance must be less than 10 K ohms. I suspect that the same requirements apply to POTS phones. If you are working with a simple, loop powered POTS phone, I think you will have difficulty getting a USA version approved in most European countries. In Europe, most countries place strict requirements on ringer response, return loss, speech levels, and frequency response. Most USA phones will fail one or more of these tests. You would probably have much better luck obtaining an approved POTS phone from an in-country supplier. This is what most companies do when all they need is a basic POTS phone to attach to their equipment. On the other hand, if your POTS function is integrated into the equipment and is not loop powered, you have more flexibility. I have had good success with designs that use transformer-coupled interfaces, with a digital signal processor to implement the POTS functions. This allows me to modify most of the ringing, dialing, and speech parameters in software, rather than hardware. In a few countries, POTS functions must be loop powered, so this approach is not universally applicable. However, the requirement for loop powered POTS can sometimes be waived, depending on the application. I hope that the above info gets you pointed in the right direction. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc.
