Can't Enter Data In Field

I have a field in my table that is varchar:1500:null, but I cannot enter any more that 994 characters. any ideas why?

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[Quotes]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[Quotes]
GO

CREATE TABLE [dbo].[Quotes] (
[QuoteID] [int] IDENTITY (1, 1) NOT NULL ,
[DateAdded] [datetime] NULL ,
[CustomerID] [int] NOT NULL ,
[ProductName] [varchar] (100) NULL ,
[RepID] [int] NULL ,
[QuoteNumber] [varchar] (30) NULL ,
[QuoteDate] [datetime] NULL ,
[QuoteTerm] [varchar] (10) NULL ,
[QuoteFOB] [varchar] (15) NULL ,
[QuoteNAIRep] [varchar] (30) NULL ,
[QuoteExpiration] [datetime] NULL ,
[Note] [varchar] (700) NULL ,
[Comment] [varchar] (1500) NULL ,
[OrderRequirement] [varchar] (1000) NULL ,
[Status] [varchar] (1) NULL ,
[DateClosed] [datetime] NULL ,
[ProductType] [varchar] (30) NULL ,
[ImageID] [int] NULL ,
[CloseMonth] [int] NULL ,
[CloseYear] [int] NULL ,
[ClosePercent] [int] NULL ,
[Segment] [varchar] (50) NULL ,
[AccountID] [uniqueidentifier] NULL ,
[ReplacedQuoteID] [int] NULL ,
[Lead] [varchar] (80) NULL
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[Quotes] ADD
CONSTRAINT [DF_Quotes_Closed] DEFAULT ('N') FOR [Status]
GO

CREATE INDEX [idx_RepID] ON [dbo].[Quotes]([RepID]) ON [PRIMARY]
GO

CREATE INDEX [indx_CustomerID] ON [dbo].[Quotes]([CustomerID]) ON [PRIMARY]
GO

CREATE INDEX [indx_QuoteID] ON [dbo].[Quotes]([QuoteID]) ON [PRIMARY]
GO

CREATE INDEX [indx_Status] ON [dbo].[Quotes]([Status]) ON [PRIMARY]
GO



[Comment] [varchar] (1500) NULL , is where I can't enter more than 994 characters.

note - I know very little about SQL, I just had the responsibility placed on me at my job. If this is not enough information to go on to throw an idea at me please let me know what else you need.

Thanks in advance