The $retry_partial command is used to specify how partial retries may be used. The default is to allow partial retries provided that the retry is made within one hour of a partially successful transmission. You can set any time limit after which the system will revert to full retry, which prevents the last few pages turning up at your recipient's fax several hours after the first part of the transmission. You can also specify the number of pages or proportion of the fax that must have already been sent before you will consider a partial retry. This can be used, for example, always to force a full retry if only one or two pages of a 20-page fax have been sent successfully.

On a partial retry the original cover sheet is never re-sent, because a partial retry cannot be considered unless at least the first page has already been sent successfully. Instead you may specify an alternate retry cover sheet using $retry_cover. System variables are available so that you can include details of how many pages have been sent and how many are still to come, as in the provided example.

When a fax transmission is retried, the retry can only start from the middle of a multiple-page TIFF file if the fax board supports this. Currently most supported boards are able to do this. The Dialogic FAX40 (VFX/40) and JCT boards is able to retry individual pages when a T.30 RTN signal (retry negative) command is received from the remote fax. This retry is specified with the $retry_page command. If the page-retry succeeds, it is taken as a normal page for the purposes of smart retry. If it fails, the normal smart retry procedures are followed.