This is an utility module that may find some use to create gated portamento effects or other slew limiting effect

It is a dual module and each submodule has its own SLEW RATE potentiometer. A GATE input jack makes it possible to control the slew function (only in the LOG mode though) : GATE OFF --> No slew, GATE ON--> Slew activated. The default status (no jack inserted in the GATE input) is Slew activated. The slew status is shown by a LED. Furthermore two toggle switches are available.

http://yusynth.net/Modular/EN/DUALSLEW/index.html