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GSM Timeslot & Frequency Specifications

These diagrams show how timeslots and corresponding frequencies are allocated in the GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), DCS (Digital Communications System), and PCS (Personal Communications Service) bands. A GSM Multiframe is the basic unit, and is 120 ms long. There are 26 Frames in each Multiframe, with each Frame being 4.61538 ms long (120 ms/26). Within each Frame are 8 Timeslots at 576.92 μs per Timeslot (577 μs in round numbers). Finally, there are 156.25 Bits per Timeslot, each Bit being 3.69231 μs long.

Tables of all GSM Frequency Bands, GSM Frequency Calculations, and GSM Timing are provided at the bottom of the page.

Data derived from ETSI EN 300 910

GSM Time Slot, Frame, & Multiframe

RF Cafe - GSM timeslot chart drawing frames timing

GSM Uplink / Downlink

RF Cafe - GSM timeslot chart drawing frames timing uplink downlink

GSM 900

RF Cafe - GSM timeslot chart drawing frames timing frequency

DCS 1800

RF Cafe - GSM timeslot chart drawing frames timing DCS

PCS 1900

RF Cafe - GSM timeslot chart drawing frames timing PCS

GSM Frequency Bands

System Band Uplink (MHz) Downlink (MHz) Channel Number
T-GSM 380 380 380.2 - 389.8 390.2 - 399.8 Dynamic
T-GSM 410 410 410.2 - 419.8 420.2 - 429.8 Dynamic
GSM 450 450 450.4 - 457.6 460.4 - 467.6 259 - 293
GSM 480 480 478.8 - 486.0 488.8 - 496.0 306 - 340
GSM 710 710 698.0 - 716.0 728.0 - 746.0 Dynamic
GSM 750 750 747.0 - 762.0 777.0 - 792.0 438 - 511
T-GSM 810 810 806.0 - 821.0 851.0 - 866.0 Dynamic
GSM 850 850 824.0 - 849.0 869.0 - 894.0 128 - 251
P-GSM 900 900 890.0 - 915.0 935.0 - 960.0 1 - 124
E-GSM 900 900 880.0 - 915.0 925.0 - 960.0 975 - 1023, 0-124
R-GSM 900 900 876.0 - 915.0 921.0 - 960.0 955 - 1023, 0-124
T-GSM 900 900 870.4 - 876.0 915.4 - 921.0 Dynamic
DCS 1800 1800 1710.0 - 1785.0 1805.0 - 1880.0 512 - 885
PCS 1900 1900 1850.0 - 1910.0 1930.0 - 1990.0 512 - 810

GSM Frequency Calculations

Frequency Band ARFCN Range Uplink Frequency
(MHz)
Downlink Frequency
(MHz)
P-GSM 900 1..124 890+0.2*ARFCN 935+0.2*ARFCN
E-GSM 900 0..124
975..1023
890+0.2*ARFCN
890+0.2*(ARFCN-1024)
935+0.2*ARFCN
935+0.2*(ARFCN-1024)
DCS 1800 512..885 1710.2+0.2*(ARFCN-512) 1805.2+0.2*(ARFCN-512)
PCS 1900 512..810 1850.2+0.2*(ARFCN-512) 1930.2+0.2*(ARFCN-512)
R-GSM 900 0..124
955..1023
890+0.2*ARFCN
890+0.2*(ARFCN-1024)
935+0.2*ARFCN
935+0.2*(ARFCN-1024)
GSM 450 259..293 450.6+0.2*(ARFCN-259) 460.6+0.2*(ARFCN-259)
GSM 480 306..340 479+0.2*(ARFCN-306) 489+0.2*(ARFCN-306)
GSM 850 128..251 824.2+0.2*(ARFCN-128) 869.2+0.2*(ARFCN-128)
GSM 750 438..511 747.2+0.2*(ARFCN-438) 777.2+0.2*(ARFCN-438)

GSM Timing

  Symbol Bursts Frames Time Rate
Symbol 1 1/8 1/1250 48/13 μs (3.692 μs) 270833/s
Burst 156.25 1 1/8 15/26 ms (576.9 μs) 1733/s
Frame 1250 8 1 60/13 ms (4.615 ms) 216.6/s
26 Multiframe 32500 208 26 120 ms 8.333/s
51 Multiframe 63750 408 51 235.4 ms 4.248/s
52 Multiframe 65000 416 52 240 ms 4.167/s
Superframe 2071875000 84864 1326 6120 ms 9.803/min
Hyperframe 4.2432E+12 173801472 2715648 3h:28m:53.760s 6.893/day