Many consultants call local sales offices. Fine - if you have a specific client whom you can identify, have convinced a salesperson that your client is a qualified prospect, don't mind dealing with a different salesperson for each client, like having your requests drop off the priority list when a hot prospect calls, and don't want to be updated on an ongoing basis. A central team, whose only aim is helping you, is usually more accommodating. Nobody sets up a program such as this out of the goodness of their heart. Charity is nice, but doesn't translate into operating budgets.
Vendors expect something for their efforts.
If you, the consultant, trust a vendor to deliver quality products which will keep your client happy, you will tend to recommend that vendor. If you don't, you won't. By giving you information, vendors hope you will grow to trust them. Consultants who are knowledgeable about Tandem can expand that prospect base. 3Com consultant relations program staffer Lorraine Valenti gives many examples of how this works in practice.