search for: impedance

...might be needed in your particular case. > > One such example that was fairly common back then was a simple transformer > that had two primary windings and two secondary windings. One could buy > them as 1:1.5 (600 ohm to 900 ohm), 1:1 (600 ohm to 600 ohm), and other > commonly used impedances. The transformer along with two 2.0 ufd > capacitors allowed DC to pass through, but changed the impedence from > one value to another. I've thought of using a transformer by itself, but obviously that wouldn't let the DC signals required for looping through. Could you give me an as...

Has anyone ever heard of this so called Dynamic Impedance matching on the ADIT 600? I called their support and they've never heard of it. We are of course having echo problems are on the far end due to digital/analog conversion on the local end using a channel bank. We have purchased an ADIT 600 and yes the complaints are "far less" however...

I understand that the X100P card is matched to a 600 ohm impedance but the UK BT phone system is not (I haven't been able to find much information on the impedance of the UK system). Has anyone come up with an easy way to match the impedance between the two so the X100P can work in the UK? Presumably a simple transformer won't do the job since it won...

...air-pressure domain. It's also similar to the way in which radar detects the presence of an airplane, by bouncing a high-frequency radio signal off of the plane. A signal reflection can occur whenever a signal, which is traveling through a transmission medium (air, wires, etc.) encounters an impedance change. In the case of a spoken echo, the impedance change is between the air (whose molecules move fairly easily in response to sound pressure) and the wall (whose molecules are bound together, and thus form a "stiff" material). In the case of radar, it occurs when the radio pulse trie...

What's the importance of the impedance matching in a FXO interface ? Kind regards, Miguel

I have an x100p which suffers from echo (no surprise there apparantly :), and a few of the things I've read about tuning out echo say the first thing to get right is the tx and rx gain, and for that you need a few different types of test lines from the telco (Telstra, Optus, whatever). Does anyone have any numbers in Australia for such lines? I think they just need to send out a tone of a

Hi, the new Grandstream release for the ATAs allows the setting of the FXS impedence, the Onhook Voltage and the Polarity Reversal. Anyone know how these should be set in Germany? -- Best regards Peer Oliver Schmidt

We have a zpool made of 4 512g iscsi luns located on a network appliance. We are seeing poor read performance from the zfs pool. The release of solaris we are using is: Solaris 10 10/09 s10s_u8wos_08a SPARC The server itself is a T2000 I was wondering how we can tell if the zfs_vdev_max_pending setting is impeding read performance of the zfs pool? (The pool consists of lots of small files).

What FXO interface methods are folks using successfully in the UK? I'm looking for good, known-to-work solutions for commercial use for two PSTN trunks on an Asterisk box. Here's the options I have, as I see it: i) Two Digium X100Ps. Pro - cheap (c. ?120), CE approved. Con - UK line impedance mismatch, with resulting echo problems, plus needs two PCI slots. ii) Digium TDM400P with two FXO modules. Pro - still fairly cheap (c. ?200), and can be set to UK line impedance, plus only uses one PCI slot. Con - Not yet CE approved. iii) Voicetronix Openline 4. Pro - reasonable price (c. ?310)...

...ne -i3 -vvvv Running with parameters: doset=0 docalibrate=1 dodump=0 startdev=1 stopdev=252 calibtype=2 waveformtype=-1 delaytosilence=0 silencegoodfor=18 dialstr=5 debug=4 Tuning module /dev/zap/1 Unable to set impedance on fd 4 Failure! ------------------ How can I fix this? Or does fxotune only tune TDM400? (My TDM400P shows a mere 1.2% echo.) Could it do "authentic" X100P? I use zaptel-1.2.10, fxotune.c Rev. 1348. Yuan Liu

Hi, I'm not sure if I just missed something somewhere along the way, but I noticed while I was going through the CVS logs that there is an option in the wcfxs module to set an "opermode" - which apparently might help with echo issues around the globe (like the ones I'm seeing - some times). So I'd love to use it and give it a go. Apparently, there are some options that

Hi, Digium's E400P has RJ45 conector and my E1 link has BNC concetor. Could someone tell me the cable pinouts to make this conection? thanks Eduardo

asterisk-users-bounces@lists.digium.com wrote: > In the following setup: > call coming from a pstn line -> into FXO card -> asterisk -> SIP > phone > > i get an incredible loud echo in the SIP phone (about 0,5-1s) > (everything i speak into SIP phone microphone i hear in its > speaker). The person calling from PSTN is not getting any echo. Make sure you're not

Hi, I have been trying to build openssh 3.4p1 on SCO Open Server xxx It requires the libcrypto.a library produced by OpenSSL. So, I downloaded and installed OpenSSL 0.9.6d. As part of the configure process for OpenSSH, 'configure' checks for version of libcrypto.a with RAND_add(). RAND_add is defined in rand_lib.c and during the build of OpenSSH, I can see that rand_lib.c is compiled

I am finding that I have to increase the txgain in zapata.conf to 8 when my X101P is connected to my BT phone line, otherwise people can hardly hear me. This then gives echo issues. Do other people have the same problem on BT lines. I was wondering if I should give BT a call and get them to increase the gain on the line. Strange though as the rxgain is OK and I don't have this problem with

I am still having unacceptable echo on my X101P and twidling with the rx/tx gain levels and echo settings appears to have no discernable effect. Some questions for those who may have more significant electrical engineering background than I. 1. This impedance match thing ... will it affect this solution having other phones in parallel with the X101P? This is done so that I can test while not having the system pickup/handle all the calls in the house until I'm ready to launch it. 2. What about the effects of it being downstream from a DSL line filte...

Hello I have serious problem with zhone z-plex 10 the device sometimes get red alarm on some channel and then the device suddenly shutdown. I try to unplugged the power chord and plug again, but the device still didn't up. I have to wait for long time to get this device up again. How can i fix this problem, so i can get this device immediately? Eris Riswanto

Hi, Has anyone in australia got asterisk running on FreeBSD? how would i pass the opermode=AUSTRALIA parameter to the wcfxs.ko module as kldload doesnt let you pass parameters to the module like modprobe in Linux. I tried to get the sysctl variable using sysctl -a it might use but nothing applicable was visible.... i need to set the impedences to 600 ohms, can someone please advice me on

...guration: Analogue Handset <--> (FXS)SPA3000(FXO) <--> PAP2 And set the Line1 dialplan on the SPA3k to '(<:@gw0>S0)' which means that as soon as I pick up the handset I get linked straight through to the PAP2, which gives me dialtone. Even in this configuration, with my impedance settings set to the Australian standard of 220+820||120nf, and the PSTN and PAP2 echo cancellers enabled (or not, and all combinations of) I get local echo as soon as I pick up the handset (I hear my voice bounced back to me). Surely this shouldn't be??? There is no hybrid involved at all! If...

Having had various issues with local vendor (begins with "V"). am looking to move to all wireless. Anyone know if current vendor can refuse to port the current land line numbers to a wireless provider? >From what I've read, the Fed's seem to say "no", they cannot refuse, or impede this. joe a.