diff --git a/doc/RUNMODEM.md b/doc/RUNMODEM.md
index b747775860..a7e246b48e 100644
--- a/doc/RUNMODEM.md
+++ b/doc/RUNMODEM.md
@@ -464,7 +464,10 @@ sudo ./ran_build/build/nr-uesoftmodem -O ../targets/PROJECTS/GENERIC-NR-5GC/CONF
 The OAI UE can also be used in front of a OAI gNB without the support of eNB or EPC and circumventing random access. In this case both gNB and eNB need to be run with the `--phy-test` flag. At the gNB this flag does the following
  - it reads the RRC configuration from the configuration file
  - it encodes the RRCConfiguration and the RBconfig message and stores them in the binary files `rbconfig.raw` and `reconfig.raw` in the current directory
- - the MAC uses a pre-configured allocation of PDSCH and PUSCH with randomly generated payload instead of the standard scheduler. The options `-m`, `-l`, `-t`, `-M`, `-T`, `-D`, and `-U` can be used to configure this scheduler. See `./nr-softmodem -h` for more information.
+ - the MAC uses a pre-configured allocation of PDSCH and PUSCH with randomly generated payload instead of the standard scheduler. The options `-m`, `-l`, `-t`, `-M`, `-T`, `-D`, and `-U` can be used to configure this scheduler.
+ - Options `-Dmod`, and `-Umod` were introduced to enable scheduling PDSCH/PUSCH on slots >= 64 in phy-test mode. (in case of >= 120Khz subcarrier spacing and FDD)
+ - For ex: `-Dmod 2' / '-Umod 2` allocates every 2nd slot for PDSCH or PUSCH respectively.
+ - See `./nr-softmodem -h` for more information.
 
 At the UE, the `--phy-test` flag will read the binary files `rbconfig.raw` and `reconfig.raw` from the current directory and process them. If you wish to provide a different path for these files, please use the options `--reconfig-file` and `--rbconfig-file`.