I believe IEEE 315 (was ANSI Y32.2) is the standard you are looking for. Assemblies and sub-assemblies are both listed as "A". When I rarely have to mark sub-assemblies within an assemblies I use A1A1, A1A2, etc. My regards, Steve Smith -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting Sent: Thursday, July 15, 2010 8:52 AM To: [log in to unmask] Subject: [TN] System schematic markings of assemblies Good morning, I'm looking for a standard for marking assemblies in a system schematic or block diagram. Typically assemblies will be A1, A2, etc., connectors will be J1, J2 or P1, P2, transformers will be T1, T2. So what is the standard for a PCB (PWA) within an assembly? Does it become A1A1, A1B1 or something else? Having a standard to work to (I'll assume this would be an ANSI standard) would be helpful. Thanks in advance. Phil Nutting Note: All the information contained in this e-mail and its attachments is proprietary to Kaiser Systems, Inc. and it may not be reproduced without the prior written permission of sender. If you have received this email in error, please immediately return it to sender and delete the copy you received. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------