On a ctx100 i need to have four moh channels. can i do it with single line cards ordo i need the special card.

Single line cards. The AST should work for 2 more. The first one is on the processor.

For more then that you nee to add a BSTU. I don't know what the Max per system is off the top of my head.

I think you can use at least 8 newtecky, but I'll have to verify the max (My guess is 16 though).

v.crage, weclcome to the board!

What is the current card assignment configuration in your CTX100? You may already have the SLT ports to do it.

You can have up to 15 according to the manual, by adding 2 BIOU's, each provides 3 MOH/BGM sources, a RSTU that provides up to 8 MOH/BGM sources and 1 off of the ASTU.

the manual says that the CTX 100 will support 15 MOH / BGM channels. Can I use an RSTU for channels 2 - 9 or do I have to add BIOU s first? Also my manual shows the RSTU connections as BGM , not MOH.

No, you do not have to add the BIOU cards before you can use the xSTU circuits. They will be assigned as numbers 8-15 though. You use a 8 to 600 ohm matching transformer. You can find them fairly easily at Radio Shack or an Electronics supplier.