IDSource (Tag = 22, Type: char)

Identifies class of alternative SecurityID (48)

Valid values:

'1'	CUSIP
'2'	SEDOL
'3'	QUIK
'4'	ISIN number
'5'	RIC code
'6'	ISO Currency Code
'7'	ISO Country Code
'100' ... '10000000000'

Used in:

• Indication of Interest (6)
• Advertisement (7)
• Execution Report (8)
• News (B)
• Email (C)
• New Order - Single (D)
• New Order - List (E)
• Order Cancel Request (F)
• Order Cancel/Replace Request (G)
• Order Status Request (H)
• Allocation (J)
• Don't Know Trade (Q)
• Quote Request (R)
• Quote (S)