(a). Functioning as Central Registry for receipt/despatch of mail of Service HQs & ISOs.
(b). Carrying out duplicating work of all sections of CAO`s office.
(C) Receipt of mail from all registries of Army HQ, Air HQ, Naval HQ, ISOs and office of the JS (Trg) & CAO.
(d). Despatch of mail to all registeries of Army HQs/Air HQ/Naval HQs/ISOs and office of the JS (TRg) & CAO.
(e) Distribution of mail to local offices and civil Ministries located in South Block, North Block, Rail Bhawan, Nirman Bhawan, Udyog Bhawan, Shastri Bhawan, Shram Shakti Bhawan etc.
(f). Under the Self Service Scheme, the MTS of the DGR, CGHQ,AFC, AFDC, DPR, Sainik Samachar, KSB, PBG, DGNCC, History Division, SFL Planning & Coordination, CGDA and HQ IDS are authorized to collect/deliver mail from/in CTH.
(g) Despatch of mail through Post Office - CTH dispatches mail through Post Office on behalf of CAO`s office, Security Office, Dte of Plg and Coord, Ordnance Factories in Delhi and LA (Def) after affixing service stamps.
(h). Mail pertaining to Foreign countries - Mail pertaining to foreign countries through diplomatic bag as well as to private addressees is accepted in CTH from Army HQs and ISOs only.
(i) Issue of File Numbers in Block of 100,500,1000 etc to the sections of CAO`s Office for their official use.
(k). Stamps are issued to CAO`s office and ISOs for dispatch of Speed Post letters.