CCNA Voice / CCNA Routing & Switching Comparison

Hi,
I'm currently in the process of studying to re-certify my CCNA Routing & Switching but realized I have until this summer to do it, so I might as well go for the 640-461 which will re-certify my CCNA Routing & Switching and give me the CCNA Voice too.
At first I assumed the CCNA Voice would share a lot of the content of the regular CCNA curriculum with the majority of it be centered on VOIP, but the more I look into this, it seems like the 640-461 doesn't really build on the base CCNA at all. How much do the CCNA R&S and CCNA Voice have in common?
Also, since I'm learning this from the ground up, I need a good book to read cover to cover... any recommendations? I really like Tod Lammle's Sybex books and have used them for all my other certs, but there's not one available for 640-461. In fact the only book I keep coming back to is this Official Cisco 640-461 Cert Guide. I've heard the Cisco press books are generally bad and have tried to avoid them so I want to know what else is out there.
Also, any other general advice for someone trying to self study for free?
Thanks!
I'm currently in the process of studying to re-certify my CCNA Routing & Switching but realized I have until this summer to do it, so I might as well go for the 640-461 which will re-certify my CCNA Routing & Switching and give me the CCNA Voice too.
At first I assumed the CCNA Voice would share a lot of the content of the regular CCNA curriculum with the majority of it be centered on VOIP, but the more I look into this, it seems like the 640-461 doesn't really build on the base CCNA at all. How much do the CCNA R&S and CCNA Voice have in common?
Also, since I'm learning this from the ground up, I need a good book to read cover to cover... any recommendations? I really like Tod Lammle's Sybex books and have used them for all my other certs, but there's not one available for 640-461. In fact the only book I keep coming back to is this Official Cisco 640-461 Cert Guide. I've heard the Cisco press books are generally bad and have tried to avoid them so I want to know what else is out there.
Also, any other general advice for someone trying to self study for free?
Thanks!
Comments
When you work in a voice support role though, the Route and Switch experience really is necessary for troubleshooting, as there is a lot of layer 3 / layer 2 issues that can arise between Phone A and Phone B over a WAN.
Is there any specific reason you are studying Voice?
They are probably prepping you for an entry into the enterprise CUCM environment, which is GUI-centric. I don't know any respectable partners who setup CME via the GUI though lol and I've bailed out several people who have attempted it