The standby switch puts the modem into "stanby mode." Essentially, it is not completey "off" in this state, but the RJ45 and USB interfaces are turned off, essentially disconnecting the computers/routers from the internet.
I never found much use for it. It was mostly a nuisance, because I would bump it when working on things, and then lose my connections.
I was relieved to find the button missing on the 5101U I use now.
I believe it also has a USB port, as indicated from Motorola's spec sheet: # Optional Installation Assistant available (models SB5101U/UE) on CD-ROM guides you through installation on the PC # Optional 1.1 USB data port available (models SB5101U/UE)
"Operationally the Motorola SB5101 series modems are exactly the same as required by the CableLabs 1.1 & 2.0 DOCSIS certification. In late 2009 Motorola introduced the more cost effective SB5101N, that only has an ethernet RJ-45 port and removed the USB driver CD from the package. The SB5101U retained the USB 2.0 and Ethernet port and continued to include the USB driver CD and it's corresponding higher cost required because of the USB feature." (From the Motorola Modem FAQs @ http://www.homenetworkingdepot.com/html/file01(general)/faq/moto.faq.html)
I have the SB5101U and it does not have the standby switch. What would be the benefit of a standby switch?? By the way, the rental I returned to Comcast did have a standby switch. Is there a real danger in not having a standby switch??
My own sb5101 does come with a standby button on the top. From the manual, http://www.secable.com/files/sb5101.pdf - The SB5101 series also features a standby switch that temporarily disconnects the modem from the PC, thus allowing for a greater degree of security when the user is not surfing while keeping the modem on the network, thus allowing the modem to be monitored, updated, and maintained by the MSO continuously. MSO stands for Multiple System Operator. MSO is the industry term for "cable company". Each cable TV installation serving a community is known as a "cable system", and the operator of the system is called the "system operator". Most system operators run cable systems in more than one community. Therefore, the vast majority of them are Multiple System Operators.
From what I understand, the modem is always on, even if you turn of ur computer, so you always have an instant connection to the internet. Since you are always connected, your computer could be compromised by any viruses that could penetrate your firewall as well as spyware. The standby button will will block potential unauthorized access while you are away by suspending your connection to the internet. When you are ready to resume work, press the stanby button to resume your connection. If you have a web page open when you go to standby, it will suspend the connection to that web page and when you release the stanby then it will reconnect to any pages you have open. It sounds useful if you are away from your computer for a long period of time, like going out or going to sleep, but if you have a dependable firewall than there should be no need for using the standby. Anyone disagree with my understanding?