Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
A "line card" is described on this Wiki page, http://en.wikipedia.org/wiki/Line_card, as "A line card or digital line card is a modular electronic circuit on a printed circuit board that interfaces with a telecommunications access network." So, network chassis devices often use the term for a card that provides network transport line termination too, aka media (e.g. Ethernet) ports.
A "service module" on chassis network devices supports some service feature other than transport media line termination. The service feature provided might be already available on the device (the service is hardware accelerated), e.g. encryption, a service feature might be enhanced, e.g. Firewall, or a service feature that's not available at all until the module is added, e.g. Wireless controller.
