|If the sound adapter is built into the mboard, IT'S NOT A SOUND CARD !|
Any device adapter that's built into the mboard IS NOT A CARD !
if the speakers require a digital connection, the computer's mboard built in sound adapter, or sound adapter installed a mboard slot (which IS a sound CARD), must have a single digital out jack to connect them to - that's usually an RCA jack (female) , or a fiber optic jack, on the computer.
Do other speakers work ?
If no speakers work, you need to install "drivers" for the sound adapter because they're not built into Windows itself.
Look in Device Manager to see if the sound adapter is flagged as not working .
(RIGHT click on My Computer - Properties - Hardware - Device Manager.)
If you search the web using: Boston Acoustics BA735, there are lots of "hits" that say they're not compatible with connecting them to many sound adapters.
Optical Digital Out and Boston Acoustics BA735 Speaker System
*** Not all digital audio connectors are usable with each other! ***
One popular "digital-only" speaker system, the Boston Acoustics BA735, has
been brought to our attention by several customers trying to use it with
our current soundcards.
All of our current soundcards come equipped with "Toslink" optical digital
The Boston Acoustics BA735 has an input labeled "Digital In" that is on a 1/8"
mini-phone jack. What it doesn't tell you is that this is a coaxial
("electrical S/PDIF") digital input, which is NOT DIRECTLY COMPATIBLE with
a Toslink optical digital output (as supplied on our soundcards).
If it's an 1/8" (mini phone) plug (male) cable coming from the speakers, it's NOT compatible with plugging it into an 1/8" (stereo) jack on the computer or sound adapter in a slot that's meant for regular speakers.
"how do i find what kind of motherboard i have"
For older Acer desktop systems, the mboard was made by Acer - an AOpen (Acer Open) model - AOpen and the model number was printed on the surface of the mboard in obvious larger characters - the info about the mboard was on the AOpen web site - but I don't know if that still applies.
Otherwise, you're limited to the following info...
Aspire T135 Series Specifications
Audio Realtek ALC655 CODEC
5.1 channel audio support
ALC655 Data sheet
There may be info about speaker connections in this, whether it has a digital audio jack or not, but it may be so generic that it's useless.
Aspire T135 Series User Guide: