From: [email protected] (Lars Poulsen) Subject: RE: Filter for Germany At 04:14 PM 3/31/97 -0800, Duane Marcroft wrote: >I'm very surprised tax pulses are transmitted in such a trashy way. >Neglecting zero start or an eponential rise of tax pulses flys in the face >of good and reasonable telecom engineering. I you or I did that the PTT's >would be down on us very quickly. > >I don't have much patience with such poor engineering practices. Faced >with the stringent telecom requirements of the PTT's in question I have to >think this smacks of a double standards. i.e. don't do as I do, do as I >say.
Siemens built very good electromechanical switches in the 1950's, and many of them are still in service. In the era of electromechanical switches, it was normal to have an always-running tone generator and switch it in and out with relays. Before the age of solid-state switches (Thyristors) it was hardly possible to do the switching on a zero-crossing. >As much as U.S. telecom practices are maligned by engineers and PTT's >outside of this country, this kind of signal generation in not allowed. >Part 68 is a double edged sword, it also controls the approval of CO >equipment. I bet you could still find a few steppers in service here and there, even in the US. Although "equal access" killed most of them off, every year or so brings a newspaper article about the "Last surviving mechanical central office [is] being decommissioned". (I think the PANEL switches are all gone, though.) / Lars Poulsen [email protected] +1-805-562-3158 OSICOM Technologies (Internet Business Unit) (formerly RNS) 7402 Hollister Avenue Manager of Remote Access Engineering Goleta, CA 93117 Internets designed while you wait
