You might want to try this site,it might help you understand....73 Clint

http://www.smartdraw.com/specials/electrical.asp?id=41662

Ian,
Please read the below from a site i found :

Please note that this microphone is design with studio and broadcast applications in mind rather than amateur radio use. This is a balanced line 3 pin XLR and works into professional mixers, EQ such as the Behringer MX 620, Julius Jones W2IHY, etc. Does not include mic cable. Shipped in a padded carry case. Please note that this mic is now produced with a flat black body with a silver wind screen as shown above (not the earlier bronze lacquer body and gold screen).

NOTE:
This mic is not designed for traditional ham radio use, and will not work in a conventional manner with most amateur transceivers.

Specifications:
Generating Element: Dynamic
Body: Mate Steel body is zinc die cast
Frequency Response: 40 to 18,000 Hz
Impedance: 600 ohms balanced
Connections: Pin 1 Shield ground, Pin 2 + , Pin 3 -
Output Level: -55dB @ 1,000 Hz.
Polar Pattern: Cardioid, uniform front to back discrimination
Diaphragm: Large diameter low-mass aluminum
Finish: Flat Black with silver wind screen
Net Weight: 14 oz.

You might want to try this link,good luck...Clint

http://www.ham.dmz.ro/yaesu/vx-7r-homebrew-sdm-interface.php

Sorry for the mistakes the link is below:

http://www.manualmall.com/TE_ZC.html

Found a link that sells the instruction manual fot he tt45b model...Clint

http://www.manualmall.com/TE_ZC.html

You might want to try this link under yaesu check out the manuals section,i hope this helps you out...Clint

http://www.mods.dk/

n try this link under yaesu tab.....73 de Clint vk2acm

http://www.mods.dk/

Dave you might try this link and look under manuals it might be what your looking for...73 de Clint VK2ACM

http://mods.dk/

Sorry i forgot the link....

http://mods.dk/

I am not sure if this link will help you,i did find on this page advising of secondary menu options,not sure though if this is the info your requiring...73 es good luck...clint vk2acm

Also you might try this site...clint

http://www.eserviceinfo.com/index.php?what=search2

Im not sure if this site will help you,it does have alot of schematics...73 clint

http://www.cqham.ru/sch_eng.html

Cliff since you stated that this is a cable signal that you receive for your viewing,is this interference on one or two cable channels or is this on all the channels?

Due to some of the channels that you would watch are also located within the 2m band spectrum,sorry to say no matter what you do to try and eliminate it ,it will probably still be there.I hope this help's somewhat....73 Clint

Bob,
I am not sure if this site will help you you may want to check it out,73 de clint

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=7226

You might want to try PROCW it's a free program i have been using it for year's now and find it great,you can build up a small optoisolator inside a db9 shell and that's it the keyboard key's the rig,it has a buffering for your messages,type ahead window,for free you cant beat it....73 es good luck...de clint vk2acm