channel-group timeslots on cisco 1721 router

A timeslot is equal to 64kb of bandwidth.

These commands create one channel-group (basically an interface) with 128kb of bandwidth. A second channel-group with 128kb. A third with only 64kb and so on.

You can then use these channel-groups

int e1/0:1
 ip address 192.168.1.1 255.255.255.0
 bandwidth 128
int e1/0:2
  ip address 192.168.2.1 255.255.255.0
  bandwidth 128
 int e1/0:3
  ip address 192.168.3.1 255.255.255.0
  bandwidth 64
 int e1/0:4
  ip address 192.168.4.1 255.255.255.0
  bandwidth 64
 
etc., etc., etc.

Thanks for feedback what are advantages of creating channel groups timeslots
Please explain

On a router, you could use it to create different interfaces for different traffic types.

timeslots 1-2 what does the number mean

A T1 has 24 64kb timeslots (total is 1.544mbps). An E1 has 30 timeslots. Timeslots 1-2 would be used to create a channel-group of 2 timeslots (1 & 2) for a total of 128kbps.

what is this command meaning on router

Controller E1 1/0
 framing NO-CRC4