The only merchant services you can use within QuickBooks Point of Sale is QuickBooks POS Merchant Services.  If you want to use a different merchant account, you have to process the credit card information outside POS and manually re-enter the sale in POS.  You'll also have to do all your batching and depositing manually as well.  It works but it's a major pain, so most people end up switching at some point.

If you're interested, we're currently offering a few specials:

•  Get a free Integrated Pin Pad/Credit Card Reader (Ingenico i3070), a $289.95 value, when you purchase (or upgrade) QuickBooks Point of Sale and are approved for a QuickBooks merchant services account.

•  Plus try QuickBooks merchant services risk-free – pay no setup fees or monthly fees for 60 days, save $135.85!. 

Also, if you're already using a different merchant account service we'll try to meet or beat their current fees.  All we need is three months of statements to get a quote started.