Tick Size Pilot Market Maker Transaction Data Technical Specification 2. CHX Contacts This section includes contact information that you may need. • CHX Control Room Operations o ControlRoom@hx.com o (312)663-2606 • CHX Trading Operations o (312)663-2038 • CHX Trouble Desk o CTrbldesk2@hx.com o (312)663-2111 Revision Number: 1 CHX Proprietary & Confidential (See Page ii) .