need help with nortel meridian 61c 1

[kbbnk]

we have a nortel meridian 61c with a Miran card. The problem is the music on hold plays fine when heard directly from the switch but this meridian is hooked to a passport in one country which communicates to another passport in the US thru IPLC and ultimately the Passport in US is interfaced to the PSTN. The problem is when users are put on hold thru' this route the music coems out distorted and plays intermittently. can anyone shed light on what could be the problem ?

 

[cooc1234]

As I understand, the problem is a technology of compressed voice that Passports use to transmit voice. Passport packs voice into small cells and sends them as data. If it is configured as Voice Networking, you can use 8 times compression (look at a G729... protocol description of a Passport). It means that every 64k voice channel is given only 8k in Passport channel. That is why your music is distorted (greater bandwidth of music then of speech). Voice Networking does not allow you to extend bandwidth, but Voice transport allowes to use bigger bandwidth channels (if it really matters and needed). I used to work with Passports 3 > years ago, sorry if this may be a little not up to date.

 

[kbbnk]

thanks a bunch, but is there a way we could resolve this ?
'coz its important for our customers to get normal music.
External audio source or any such ? would you happen to know ?

 

[cooc1234]

Hi. As always, if you want more quality, you have to sacrifice resources.
If I were you, I would use Voice Transport rather then Voice Networking, but if Voice Networking is used by network design and there are many nodes in the network, you will not be able to change it. Next thing, check if "silence suppression" on both Passport's is set to "off". This should help with "intermittency". But not always. The sacrifice in this case will be that each vs will hold it's bandwidth even in "no voice" condition. But switching between "voice" and "no voice" will be much smoother. To improve the quality of music, you can test different types of music (not really effective) or go to different voice transport protocol, e.g. instead of G729 with 8K channels use G728 or G726 (16K or 32K each channel). But this will decrease number of channels twice or 4 times which is HUGE sacrifice.... If something better comes to my mind, I will draw a line... Thanks... Alex.

 

[kbbnk]

Hi Alex,
Would you happen to know how to configure so that my music source is not the flash memory but external audio. Currently we use the music that's stored in the flash memory and the way its configuerd is music route -> Miran card slot # -> channel # on the Miran... this means it will select music from the flash memory. Now, to configure it such that the music source is external, What will be the mapping ? for instance my music route is 40, , miran card is in slot 14, and music from flash memory is channel 0 in table LD14... what now ??

 

[Mankyway]

Hi KBBNK

Good points made above, although the Passport should compress and then decompress at the other end, What protocol is linking the two Passports? ATM? and are you running data over the same circuit? What is the quality of Voice over the same circuit? Are you using the above mentioned Voice Transport Voice Networking or are you using the Passport Voice Gateway?

I thought I had this type of problem once, all crackly and intermittent, but it turned out to be a Spice Girls song That was being played

 

[cooc1234]

Hi, To program external music, you can use one of the ports of XUT card (Universal Trunk), route is the same, trunk in ld 14 TYPE MUS. Connect your external musical source line output (0,25 - 0,5V) directly to the XUT port. If you need more information, let me know or look at the "Feature Guide", description of "Music on hold" feature.
.........
The above message is a good point, especially if the passport network uses public Frame Relay or ATM (non-Nortel proprietary)channels.
...Alex...