When a message is sent to a pager that is registered with Spok Mobile, a Two-Way Messaging icon displays in the Compose a Message screen.
NOTE: When paging an on-call group, message group, or a personal message group member on a device that is registered with Spok Mobile, note that if there are any attachments to the message, such as a picture, the message will not be sent. For best results, do not add attachments to a message that may be sent to a Spok Mobile device.