QUESTION:
What are the order numbers for crimp contacts/tools for the front connector of the S7-400?

ANSWER:
Crimp contacts for the front contactors for S7-400 and the relevant tools have the following order numbers:

Order number	Ordering data
6XX3070, 250 pcs	Crimp contacts
6ES5 497-8MA11	Unlocking tool for crimp contacts (for S5 and S7)
6ES5 497-4UC11	Unlocking tool for crimp contacts (for S5)
6XX3071	Crimping tool

Table 1: Order numbers

Note:
The crimp contacts can also be used for S5 modules. The tools are needed in case of a change to remove contacts already mounted in a connector or to connect the contacts to the cables.

Fig. 1: S7/S5 tool

Fig. 2: S5 tool

Notes on how to employ the unlocking tool for crimp contacts:

Take the front connector and first remove the cover. Unlocking is always down from the cable connection side that has now been made free. Under the pin designation of each contact next to each contact cavity there is a small slit going off to the right. Insert the unlocking tool with its metal lug into this slit. 

The position of the tool is such that the longitudinal indentation on the narrow side of the grip faces the cavity wall. The cable coming away from the crimp contact is laid in this indentation. Now you push the tool into the slit as far as it can go. This unlocks the contact and at the same time it is pulled back out of the cavity with the cable and tool.

If the contact has been pushed into the cavity incorrectly without a crimped cable and has to be pulled out again, then you must use a screwdriver, for example, to push from the front so that the cable is released from the cavity.