Yealink SIP-T48G Administrator's Manual page 22

Microsoft Lync Edition Administrator's Guide for SIP-T2_Series and T4_Series IP Phones
1) Attach the stand and the optional wall mount bracket:
For SIP-T48G:
Note
The top two slots on SIP-T48G IP phones are plugged up by silica gel. You need to pull out
silica gel before attaching the wall mount bracket.
10
Desk Mount Method
Wall Mount Method (Optional)