redeemable,irredeemable debentures

Debenture is a debt instrument issued by the company to 
raise the funds. 

Types of Debentures : Secured Debentures, Unsecured 
Debentures, Redeemable Debentures, Irredeemable debentures, 
convertable debentures, non convertable debentures, 
cumulative debentures, noncumulative debentures

When a company borrows money from investing people it 
issues bonds which is stamped with official seal is called 
as debentures
types of debentures:
security point of view 
recording point of view 
performance pont of view
conversion point of view
priorty point of view

debenture is a secured loan.
types of debenture
naked debenture
redeemeble debenture
irredemable debenture

"A Debenture is a document under company's, which provide 
payment of principal sim & interestthereon at regular 
intervals.

Types :
1.Convertible
2.Non-Convertible
3.Zero Coupon
4.Cumulative
5.Non-Cumulative

From different point of view:
Redemption :  Redeemable and irredeemable
Security :  mortgage debenture and naked or simple debentures
Record:  registered debenture and bearer debentures 
Priority: first debentures and second debentures 
Convertibility: Convertible and Non convertible