I have a problem. Currently I have 7609 with SIP-200 module installed and 2 SPA-8XCHT1/E1 sub modules on that SIP-200. I want to upgrade that SIP-200 to SIP-400 which provides more power. My question is, are they compatible. I dont have the hardware to test this compatibility. I have read SIP-400 datasheet. It says that the are compatible, but when I tried it on the dynamic configuration tool, when I choose SIP-400 as one of the module, it didnt offer SPA-8XCHT1/E1 as its sub module. This is what made me doubtful about the compatibility. So, if anyone has this configuration on their routers, please share... Thanks a lot guys.