-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 At 10:45 AM 3/25/00 -0800, Jane Ifurung wrote: >--- David VanHorn wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >Thanks for replying. >> >> >At least I do know now that I've wire-wrapped my >> >project in a "good" way. There's no noise. The dial >> >tone, busy tone, and speech are audible and smooth. >> >(I've got some small problems, anyway--- like I >> can't >> >balance accurately the speech network). >> >> Did you include the proper reactance as well as >> resistance in your >> balancing impedance? > >Actually, I don't know what components should be used >because in the first place, I don't know the impedance >of the telephone line. US-Centric phone systems are 600 ohms, with a reactive component that I can't recall offhand. Canada, IIRC uses 900 for some reason, other countries vary. tahe SLIC I'm using is >MH88617AT from Mitel Semiconductor. Hmm. Are you SURE this slic is designed to interface to a CO line? Most are not. That would be bad. In my experience, SLIC (Subscriber Line Interface Circuit) provides the basic circuitry needed to simulate a CO line to connected telephone devices, like for the internal lines of a PBX. Can you give me a URL to a datasheet (or email it, I can take big emails) >I need your help. Do I continue using the components >for 600 ohms and just vary the length of the wire? No. >Or >is it better to use a fix length of wire and use >trial-and-error to arrive at at the correct value of >the balancing network? The length of the wire shouldn't even enter into your figures, except that the overall loss will be higher. >Maybe this is the reason why when I dial, only the >number "0" (operator) is being detected. See above, you may have larger problems. -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use iQA/AwUBON0+TIFlGDz1l6VWEQKdsQCeJSDwttthZbRlKpbrsk7k6IB7StQAnjiu BBeTsr7CYtLYfYWCCUFPMmKG =uizc -----END PGP SIGNATURE-----