Trunk DOSA

Feature Name : Trunk DOSA (Direct Outward System Access)

User Code : 

Programming Code : Explained below

Default Value : DOSA on all trunks OFF

Feature Type - Programming / User : Both

Description of the Feature : 

DOSA is useful to make STD/ISD calls on STD trunk from outside of your company or EPABX installed location. It gives the facility to make use of the phisically connected outgoing trunk line to the EPABX from remote end. It requires 2 trunk lines connected to the EPABX - one for incoming call and the other one to dial out using DOSA.

DOSA facility is associated with your own extension number and protected with password to prevent misuse.

How to Use : 



Trunk Line(dialing) 

DOSA on/off (day) 

DOSA on/off (night) 






You Hear

You are at remote end. Dial your office telephone number where Centrex EPABX is installed 

Ring back tone. Then, you get music / voice generated by the EPABX, followed by Beep tone for further dialing process.

Dial # + your extension number + Extension password 

Fast beep tone (if you dial the right password). Else, you will get error tone and a chance to try 2 more times. 

Dial trunk Access Code(71~78 / 0 / 5) of outgoing trunk. 

BSP Trunk Dial Tone 

 Dial desired telephone number

External Ringing tone. Begin conversation with the dialed party 

Useful reference points for DOSA (must read before using)

  1. In DOSA mode, if you wish to disconnect the Telephone Line and Dial a different Telephone number,Dial # during conversation;
  2. In Dosa mode, if you wish to disconnect entire conversation with both the Telephone Lines, Dial * ;
  3. After 3 min (programmable time) you will get DOSA Inactivity alert tone. If you  wish to extend your call for next 3 minutes, dial any digit except # & * keys;
  4. You have to change your default extension password from 0000 to new 4-digit password;
  5.  Before using DOSA facility to access on STD/ISD lines, its better to test and operate it on few local calls;
  6. To avoid confusion with customer, it is suggested to take responsibility undertaking confirmation letter for DOSA facility and its uses, as there is a chance of misusing the lines;
  7. Centrex Telecom withdraws the responsibility above DOSA facility and its uses. Although we created maximum security to stop misuse, user attention is a must.
Restrictions : 

Modifications / Suggestions :